The smallest divisions of the arteries located between the muscular arteries and the capillaries.
The innermost layer of the three meninges covering the brain and spinal cord. It is the fine vascular membrane that lies under the ARACHNOID and the DURA MATER.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
The minute vessels that collect blood from the capillary plexuses and join together to form veins.
Central retinal artery and its branches. It arises from the ophthalmic artery, pierces the optic nerve and runs through its center, enters the eye through the porus opticus and branches to supply the retina.
The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.
The circulation of the BLOOD through the MICROVASCULAR NETWORK.
Drugs used to cause dilation of the blood vessels.
The nonstriated involuntary muscle tissue of blood vessels.
The part of the face that is below the eye and to the side of the nose and mouth.
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
A complex of cells consisting of juxtaglomerular cells, extraglomerular mesangium lacis cells, the macula densa of the distal convoluted tubule, and granular epithelial peripolar cells. Juxtaglomerular cells are modified SMOOTH MUSCLE CELLS found in the walls of afferent glomerular arterioles and sometimes the efferent arterioles. Extraglomerular mesangium lacis cells are located in the angle between the afferent and efferent glomerular arterioles. Granular epithelial peripolar cells are located at the angle of reflection of the parietal to visceral angle of the renal corpuscle.
Microscopy in which television cameras are used to brighten magnified images that are otherwise too dark to be seen with the naked eye. It is used frequently in TELEPATHOLOGY.
The neural systems which act on VASCULAR SMOOTH MUSCLE to control blood vessel diameter. The major neural control is through the sympathetic nervous system.
Drugs used to cause constriction of the blood vessels.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
The minute vessels that connect the arterioles and venules.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
An inhibitor of nitric oxide synthetase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. (Neurochem Res 1995:200(4):451-6)
The arterial blood vessels supplying the CEREBRUM.
A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.
Porphyrins with four methyl, two ethyl, and two propionic acid side chains attached to the pyrrole rings.
A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.
The flow of BLOOD through or around an organ or region of the body.
The circulation of the BLOOD through the vessels of the KIDNEY.
The veins and arteries of the HEART.
The vessels carrying blood away from the heart.
An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.
Genetically developed small pigs for use in biomedical research. There are several strains - Yucatan miniature, Sinclair miniature, and Minnesota miniature.
The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
Abnormal enlargement or swelling of a KIDNEY due to dilation of the KIDNEY CALICES and the KIDNEY PELVIS. It is often associated with obstruction of the URETER or chronic kidney diseases that prevents normal drainage of urine into the URINARY BLADDER.
The blood vessels which supply and drain the RETINA.
A CALCIUM-dependent, constitutively-expressed form of nitric oxide synthase found primarily in ENDOTHELIAL CELLS.
A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.
A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.
The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. (Stedman, 25th ed)
A non-steroidal anti-inflammatory agent (NSAID) that inhibits the enzyme cyclooxygenase necessary for the formation of prostaglandins and other autacoids. It also inhibits the motility of polymorphonuclear leukocytes.
A strain of Rattus norvegicus used as a normotensive control for the spontaneous hypertensive rats (SHR).
A strain of Rattus norvegicus with elevated blood pressure used as a model for studying hypertension and stroke.
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).
The relationship between the dose of an administered drug and the response of the organism to the drug.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
A nonapeptide messenger that is enzymatically produced from KALLIDIN in the blood where it is a potent but short-lived agent of arteriolar dilation and increased capillary permeability. Bradykinin is also released from MAST CELLS during asthma attacks, from gut walls as a gastrointestinal vasodilator, from damaged tissues as a pain signal, and may be a neurotransmitter.
A stable prostaglandin endoperoxide analog which serves as a thromboxane mimetic. Its actions include mimicking the hydro-osmotic effect of VASOPRESSIN and activation of TYPE C PHOSPHOLIPASES. (From J Pharmacol Exp Ther 1983;224(1): 108-117; Biochem J 1984;222(1):103-110)
The finer blood vessels of the vasculature that are generally less than 100 microns in internal diameter.
An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.
Central retinal vein and its tributaries. It runs a short course within the optic nerve and then leaves and empties into the superior ophthalmic vein or cavernous sinus.
Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.
Compounds or agents that combine with cyclooxygenase (PROSTAGLANDIN-ENDOPEROXIDE SYNTHASES) and thereby prevent its substrate-enzyme combination with arachidonic acid and the formation of eicosanoids, prostaglandins, and thromboxanes.
A group of compounds derived from unsaturated 20-carbon fatty acids, primarily arachidonic acid, via the cyclooxygenase pathway. They are extremely potent mediators of a diverse group of physiological processes.
An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.
A tissue preparation technique that involves the injecting of plastic (acrylates) into blood vessels or other hollow viscera and treating the tissue with a caustic substance. This results in a negative copy or a solid replica of the enclosed space of the tissue that is ready for viewing under a scanning electron microscope.
A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.
A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.
A layer of the peritoneum which attaches the abdominal viscera to the ABDOMINAL WALL and conveys their blood vessels and nerves.
A diphenylbutylpiperidine that is effective as an antipsychotic agent and as an alternative to HALOPERIDOL for the suppression of vocal and motor tics in patients with Tourette syndrome. Although the precise mechanism of action is unknown, blockade of postsynaptic dopamine receptors has been postulated. (From AMA Drug Evaluations Annual, 1994, p403)
Treatment process involving the injection of fluid into an organ or tissue.

Calcium responses induced by acetylcholine in submucosal arterioles of the guinea-pig small intestine. (1/2323)

1. Calcium responses induced by brief stimulation with acetylcholine (ACh) were assessed from the fluorescence changes in fura-2 loaded submucosal arterioles of the guinea-pig small intestine. 2. Initially, 1-1.5 h after loading with fura-2 (fresh tissues), ACh increased [Ca2+]i in a concentration-dependent manner. This response diminished with time, and finally disappeared in 2-3 h (old tissues). 3. Ba2+ elevated [Ca2+]i to a similar extent in both fresh and old tissues. ACh further increased the Ba2+-elevated [Ca2+]i in fresh tissues, but reduced it in old tissues. Responses were not affected by either indomethacin or nitroarginine. 4. In fresh mesenteric arteries, mechanical removal of endothelial cells abolished the ACh-induced increase in [Ca2+]i, with no alteration of [Ca2+]i at rest and during elevation with Ba2+. 5. In the presence of indomethacin and nitroarginine, high-K+ solution elevated [Ca2+]i in both fresh and old tissues. Subsequent addition of ACh further increased [Ca2+]i in fresh tissues without changing it in old tissues. 6. Proadifen, an inhibitor of the enzyme cytochrome P450 mono-oxygenase, inhibited the ACh-induced changes in [Ca2+]i in both fresh and Ba2+-stimulated old tissues. It also inhibited the ACh-induced hyperpolarization. 7. In fresh tissues, the ACh-induced Ca2+ response was not changed by apamin, charybdotoxin (CTX), 4-aminopyridine (4-AP) or glibenclamide. In old tissues in which [Ca2+]i had previously been elevated with Ba2+, the ACh-induced Ca2+ response was inhibited by CTX but not by apamin, 4-AP or glibenclamide. 8. It is concluded that in submucosal arterioles, ACh elevates endothelial [Ca2+]i and reduces muscular [Ca2+]i, probably through the hyperpolarization of endothelial or smooth muscle membrane by activating CTX-sensitive K+ channels.  (+info)

Interaction of amylin with calcitonin gene-related peptide receptors in the microvasculature of the hamster cheek pouch in vivo. (2/2323)

1. This study used intravital microscopy to investigate the receptors stimulated by amylin which shares around 50% sequence homology with the vasodilator calcitonin gene-related peptide (CGRP) in the hamster cheek pouch microvasculature in vivo. 2. Receptor agonists dilated arterioles (diameters 20-40 microm). The -log of the concentrations (+/- s.e.mean; n = 8) causing 50% increase in arteriole diameter were: human betaCGRP (10.8 +/- 0.3), human alphaCGRP (10.8 +/- 0.4), rat alphaCGRP (10.4 +/- 0.3). Rat amylin and the CGRP2 receptor selective agonist [Cys(ACM2,7]-human alphaCGRP were 100 fold less potent (estimates were 8.5 +/- 0.4 and 8.2 +/- 0.3 respectively). 3. The GCRP1 receptor antagonist, CGRP8-37 (300 nmol kg(-1); i.v.) reversibly inhibited the increase in diameter evoked by human alphaCGRP (0.3 nM) from 178 +/- 22% to 59 +/- 12% (n = 8; P < 0.05) and by rat amylin (100 nM) from 138 +/- 23% to 68 +/- 24% (n = 6; P < 0.05). CGRP8-37 did not inhibit vasodilation evoked by substance P (10 nM; n = 4: P > 0.05). 4. The amylin receptor antagonist, amylin8-37 (300 nmol kg(-1); i.v.) did not significantly inhibit the increase in diameter evoked by human alphaCGRP (0.3 nM) which was 112 +/- 26% in the absence, and 90 +/- 29% in the presence of antagonist (n = 4; P < 0.05); nor that evoked by rat amylin (100 nM) which was 146 +/- 23% in the absence and 144 +/- 32% in the presence of antagonist (n = 4; P > 0.05). 5. The agonist profile for vasodilatation and the inhibition of this dilatation by CGRP8-37, although not the amylin8-37 indicates that amylin causes vasodilatation through interaction with CGRP1 receptors in the hamster cheek pouch.  (+info)

Spread of vasodilatation and vasoconstriction along feed arteries and arterioles of hamster skeletal muscle. (3/2323)

1. In arterioles of the hamster cheek pouch, vasodilatation and vasoconstriction can spread via the conduction of electrical signals through gap junctions between cells that comprise the vessel wall. However, conduction in resistance networks supplying other tissues has received relatively little attention. In anaesthetized hamsters, we have investigated the spread of dilatation and constriction along feed arteries and arterioles of the retractor muscle, which is contiguous with the cheek pouch. 2. When released from a micropipette, acetylcholine (ACh) triggered vasodilatation that spread rapidly along feed arteries external to the muscle and arterioles within the muscle. Responses were independent of changes in wall shear rate, perivascular nerve activity, or release of nitric oxide, indicating cell-to-cell conduction. 3. Vasodilatation conducted without decrement along unbranched feed arteries, yet decayed markedly in arteriolar networks. Thus, branching of the conduction pathway dissipated the vasodilatation. 4. Noradrenaline (NA) or a depolarizing KCl stimulus evoked constriction of arterioles and feed arteries of the retractor muscle that was constrained to the vicinity of the micropipette. This behaviour contrasts sharply with the conduction of vasodilatation in these microvessels and with the conduction of vasoconstriction elicited by NA and KCl in cheek pouch arterioles. 5. Focal electrical stimulation produced constriction that spread rapidly along feed arteries and arterioles. These responses were inhibited by tetrodotoxin or prazosin, confirming the release of NA along perivascular sympathetic nerves, which are absent from arterioles studied in the cheek pouch. Thus, sympathetic nerve activity co-ordinated the contraction of smooth muscle cells as effectively as the conduction of vasodilatation co-ordinated their relaxation. 6. In the light of previous findings in the cheek pouch, the properties of vasoconstriction and vasodilatation in feed arteries and arterioles of the retractor muscle indicate that substantive differences can exist in the nature of signal transmission along microvessels of tissues that differ in structure and function.  (+info)

Neovascularization at the vascular pole region in diabetic glomerulopathy. (4/2323)

BACKGROUND: Diabetic nephropathy is associated with renal structural changes involving all of the compartments. Most characteristic is the diabetic glomerulopathy. Studies of the histological changes during the early phases of nephropathy have included the glomerulopathy and also the juxtaglomerular structures. Neovascularization, well-known in diabetic retinopathy, has also been observed in the kidney. The present study concerns estimates of frequency of neovascularization at the vascular pole region in early stages of diabetic nephropathy. METHODS: Extra efferent arterioles at the glomerular vascular pole were detected during measurements of the vascular pole area applying 1-microm serial sections through kidney biopsies. It was observed that more than one efferent arteriole existed occasionally. The present study was carried out with the aim of estimating the frequency of this phenomenon in diabetic patients and in non-diabetic controls, the diabetic patients categorized according to the level of albumin excretion rate. RESULTS: Neovascularization was first observed in IDDM patients with microalbuminuria. Some of the cases presented the phenomenon in all of the glomeruli studied. As the examinations of many kidney biopsies continued the phenomenon was observed also in the non-diabetic control group and in one IDDM patient with normoalbuminuria. However, the frequency was statistically highly significantly increased in patients with elevated albumin-excretion. Within this group a strong correlation between frequency of neovascularization and the severity of diabetic glomerulopathy is seen. CONCLUSIONS: The vascular abnormality localized to the vascular pole region is observed occasionally in the normal kidney, but the frequency is increased in patients with diabetic glomerulopathy. The abnormality may develop as a consequence of a long-standing diabetic glomerulopathy and might lead to less pronounced elevation of albumin excretion.  (+info)

Inhibition of NO synthesis or endothelium removal reveals a vasoconstrictor effect of insulin on isolated arterioles. (5/2323)

In this study we tested the hypothesis that insulin may differentially affect isolated arterioles from red (RGM) and white gastrocnemius muscles (WGM) because of their differences in function and metabolic profile. We also determined whether the responses of these arterioles are endothelium dependent and mediated by either prostaglandins or nitric oxide (NO). Arterioles were isolated, pressurized to 85 mmHg, equilibrated in Krebs bicarbonate-buffered solution (pH 7.4) gassed with 10% O2 (5% CO2-85% N2), and studied in a no-flow state. Control diameters for first-order arterioles from RGM averaged 77 +/- 8 micrometers and from WGM averaged 77 +/- 5 micrometers. Cumulative dose-response curves to insulin (10 microU/ml, 100 microU/ml, 1 mU/ml, and 10 mU/ml) were obtained in arterioles before and after endothelium removal or administration of either indomethacin (Indo, 10(-5) M) or NG-nitro-L-arginine (L-NNA, 10(-4) M). Insulin evoked concentration-dependent increases in control diameter of intact RGM and WGM arterioles of 6-26% and 9-28%, respectively. Indo was without any effect on insulin-induced dilation in RGM and WGM arterioles. Insulin-evoked dilation in both RGM and WGM arterioles was completely inhibited and converted to vasoconstriction by endothelium removal and administration of L-NNA. These results indicate that in endothelium-intact arterioles from RGM and WGM, insulin evokes an endothelium-dependent dilation that is equivalent and mediated by NO. In contrast, in the absence of a functional endothelium, insulin evokes arteriolar constriction. The finding that insulin can constrict arterioles, at physiological concentrations, suggests that insulin may play a more significant role in the regulation of vascular tone and total peripheral resistance than previously appreciated.  (+info)

Conducted signals within arteriolar networks initiated by bioactive amino acids. (6/2323)

Our purpose was to determine the specificity of L-arginine (L-Arg)-induced conducted signals for intra- vs. extracellular actions of L-Arg. Diameter and red blood cell velocities were measured for arterioles [18 +/- 1.6 (SE) micrometer] in the cremaster muscle of pentobarbital sodium-anesthetized (Nembutal, 70 mg/kg) hamsters (n = 53). Remote (conducted) responses were viewed approximately 1,000 micrometer upstream from the local (micropipette) application. Six amino acids were tested: L-arginine, L-cystine, L-leucine, L-lysine, L-histidine, and L-aspartate (100 microM each). Only L-Arg induced a remote dilation; L-lysine and L-aspartate had no effect, and the others each induced a significant remote constriction. There is a second conducted signal initiated by L-arginine that preconditions the arteriolar network and upregulates a direct response of L-arginine to dilate the remote site. This was blocked by inhibition of L-arginine uptake at the local (preconditioning) site (100 microM L-histidine or 1 mM phenformin). Arginine-glycine-aspartate (100 microM)-induced remote dilations (+3. 2 +/- 0.3 micrometer) were not mimicked by a peptide control and were prevented by anti- integrin alphav monoclonal antibody. Remote dilations were greater in animals with a higher wall shear stress for arginine-glycine-aspartate (r2 = 0.92) but not for L-arginine (r2 = 0.12). Thus L-arginine initiates separate conducted signals related to system y+ transport, integrins, and baseline flow.  (+info)

Endothelin antagonists block alpha1-adrenergic constriction of coronary arterioles. (7/2323)

We have previously observed that intracoronary administration of the alpha1-adrenergic agonist phenylephrine (PE) over a period of minutes induced both an immediate and long-lasting (2 h) vasoconstriction of epicardial coronary arterioles. Because it is unlikely that alpha1-adrenergic constriction would persist for hours after removal of the agonist, this observation supports the view that another constrictor(s) is released during alpha1-adrenergic activation and induces the prolonged vasoconstriction. Therefore, we hypothesized that the prolonged microvascular constriction after PE is due to the production of endothelin (ET). We focused on ET not only because this peptide produces potent vasoconstriction but also because its vasoconstrictor action is characterized by a long duration. To test this hypothesis, the diameters of coronary arterioles (<222 micrometers) in the beating heart of pentobarbital-anesthetized dogs with stroboscopic intravital microscopy were measured during a 15-min intracoronary infusion of PE (1 microgram. kg-1 . min-1) and at 15-min intervals for a total of 120 min. All experiments were performed in the presence of beta-adrenergic blockade with propranolol. At 120 min, arterioles in the PE group were constricted (-23 +/- 9% change in diameter vs. baseline). Pretreatment with the ET-converting enzyme inhibitor phosphoramidon or the ETA-receptor antagonist FR-139317 prevented the PE-induced constriction at 120 min (-1 +/- 3 and -6 +/- 3%, respectively, P < 0.01 vs. PE). Pretreatment with the selective alpha1-adrenergic antagonist prazosin (Prz) also prevented the sustained constriction (0 +/- 2%, P < 0.01 vs. PE) but Prz given 60 min after PE infusion did not (-13 +/- 3%). In the aggregate, these results show that vasoconstriction of epicardial coronary arterioles via alpha1-adrenergic activation is blocked by an ET antagonist and an inhibitor of its production. From these data, we conclude that alpha1-adrenergic activation promotes the production and/or release of ET, which produces or facilitates microvascular constriction of epicardial canine coronary arterioles.  (+info)

Flow regulation of ecNOS and Cu/Zn SOD mRNA expression in porcine coronary arterioles. (8/2323)

The purpose of this study was to test the hypothesis that increased flow through coronary arterioles increases endothelial cell nitric oxide synthase (ecNOS) and Cu/Zn superoxide dismutase (SOD) mRNA expression. Single porcine coronary arterioles (ID 100-160 micrometers; pressurized) were cannulated, perfused, and exposed to intraluminal flow sufficient to produce maximal flow-induced dilation of coronary arterioles (high flow; 7.52 +/- 0.22 microliter/min), low flow (0.84 +/- 0.05 microliter/min), or no flow for 2 or 4 h. Mean shear stress was calculated to be 5.7 +/- 1.0 dyn/cm2 for high-flow arterioles and 1. 6 +/- 1.0 dyn/cm2 for low-flow arterioles. At the end of the treatment period, mRNA was isolated from each vessel, and ecNOS and SOD mRNA expression was assessed using a semiquantitative RT-PCR. All data were standardized by coamplifying ecNOS or SOD with glyceraldehyde-3-phosphate dehydrogenase. The results indicate that ecNOS mRNA expression is increased in arterioles exposed to 2 or 4 h of high flow. In contrast, SOD mRNA expression was increased only after 4 h of high flow. Neither gene is induced by exposure to low flow. On the basis of these data, we concluded that ecNOS and SOD mRNA expression is regulated by flow in porcine coronary arterioles. In addition, we concluded that a threshold level of flow and shear stress must be sustained to elicit the upregulation of ecNOS and SOD mRNA expression.  (+info)

We performed experiments to test the hypothesis that endogenous adenosine acts as an essential cofactor required for eliciting angiotensin II (Ang II)-induced afferent and/or efferent arteriolar vasoconstriction. Enalaprilat (2 mg IV) was administered to anesthetized rats to reduce endogenous Ang II levels. Kidneys and blood were harvested from these animals and used for study of renal microvascular function using the in vitro blood-perfused juxtamedullary nephron technique. Arteriolar inside diameter was monitored videomicroscopically in (1) normal kidneys, (2) kidneys subjected to adenosine receptor blockade (100 mumol/L 1,3-dipropyl-8-p-sulfophenylxanthine), and (3) kidneys continuously exposed to 1 mumol/L adenosine. Under resting conditions, arteriolar diameters were similar in all three groups of kidneys, averaging 24.8 +/- 1.0 microns (n = 23) in afferent arterioles and 24.0 +/- 0.9 microns (n = 16) in efferent arterioles. In normal kidneys, adenosine (10 mumol/L) decreased both afferent ...
The major finding of the present study is that selective intrarenal nNOS inhibition by L-SMTC elicited marked decreases in renal hemodynamics and sodium excretory functions in normotensive rats and did not significantly influence renal function in Ang II-infused hypertensive rats. This finding is in a good agreement with the previous studies demonstrating an important role for nNOS in buffering TGF-mediated afferent arteriolar vasoconstriction in normotensive rats.9-11 In line with our finding is also the recent observation made by Ichihara et al13 employing the in vitro blood-perfused juxtamedullary nephron preparation that the decrease in afferent arteriolar diameter in response to L-SMTC administration was significantly less in Ang II-infused rats compared with control rats.. It has been also shown that nNOS activity, nNOS mRNA, and renin mRNA are increased in AT1A receptor gene and angiotensinogen gene knockout mice.18,19 In addition, studies evaluating the effects of sodium intake on renin, ...
Purpose.: Elevated plasma concentration of homocysteine, a sulfur-containing amino acid, is an emerging risk factor for cardiovascular diseases. Recent epidemiologic studies have confirmed that elevated homocysteine levels are associated with ocular vascular diseases; however, the direct effect of homocysteine on ocular microvascular reactivity remains unknown. We investigated whether homocysteine affects endothelium-dependent nitric oxide (NO)-mediated dilation of retinal arterioles and whether oxidative stress and distinct protein kinase signaling pathways are involved in the homocysteine-mediated effect. Methods.: Porcine retinal arterioles were isolated, cannulated, and pressurized without flow in vitro. Diameter changes were recorded using videomicroscopy techniques. Results.: Intraluminal treatment with homocysteine (1 mM, 180 minutes) significantly attenuated arteriolar dilation in response to the endothelium-dependent NO-mediated agonists bradykinin and A23187 but not in response to the ...
TY - JOUR. T1 - Vascular Endothelium and Smooth Muscle Remodeling Accompanies Hypertrophy of Intestinal Arterioles in Streptozotocin Diabetic Rats. AU - Connors, Bret A.. AU - Bohlen, H.. AU - Evan, Andrew. PY - 1995/5. Y1 - 1995/5. N2 - The purpose of this study was to document alterations in endothelial and smooth muscle cell morphology of first- and second-order intestinal arterioles after 6 months of streptozotocin-induced diabetes. Both light and scanning electron microscopic techniques were used to quantitate the changes in the microvasculature. After rendering the first- and second-order intestinal arterioles passive and processing the vessels, it was determined that these microvessels were significantly dilated in the diabetic animals. Further examination revealed that in the diabetic animals, the cross-sectional area of the endothelial layer was increased in both 1A and 2A vessels, and the smooth muscle layer cross-sectional area was significantly increased in 1A vessels. Individual ...
Aims: To study the effect of an acute increase in the arterial blood pressure on the diameter response of retinal arterioles supplying areas with focal diabetic macular oedema before and after laser photocoagulation, and control arterioles supplying areas without oedema.. Methods: In 17 diabetic patients the diameter response of arterioles after an increase in the arterial blood pressure induced by isometric exercise was studied using the retinal vessel analyser (RVA). In each patient a study arteriole supplying a focal area of macular oedema as well as a control arteriole supplying a retinal area without retinopathy lesions was selected, and the diameter response of these vessels was performed immediately before, and 1 hour and 3 months after focal laser photocoagulation of the focal oedema area.. Results: The diameter response was impaired in both study arterioles and control arterioles before focal laser photocoagulation. The treatment induced regression of the focal retinal oedema, but did ...
Skeletal muscle arterioles dilate in response to application of acetylcholine (ACh), eliciting a conducted vasodilation (CVD) that travels along unbranched segments without decrement. CVD is known to entail cell-to-cell transmission of hyperpolarization along the endothelium via gap junction channels, a purely passive mechanism. In the present thesis I study CVD in bifurcating arteriolar networks, where the pathway for hyperpolarizing current expands compared to unbranched arterioles, to test for an active component to CVD. In a separate subset of arterioles, the effect of augmenting vasomotor tone on CVD was tested using elevated O2 or phenylephrine (PE) in the superfusion solution vs. control. Male C57BL/6 mice (n=13; 10-13 weeks old) were anesthetized with pentobarbital sodium (50mg/kg, intraperitoneal injection) and maintained at 37 [degrees]C. The cremaster was carefully exteriorized and spread onto a transparent Sylgard pedestal. The tissue was maintained at 34 [degrees]C with continuous ...
The present study is the first to demonstrate that Ang II activates differing Ca2+ entry mechanisms in afferent and efferent arterioles. Our findings are thus consistent with evolving concepts concerning the segmental heterogeneity of activation mechanisms within the renal microvasculature. In the afferent arteriole, Ang II stimulates Ca2+ influx via dihydropyridine-sensitive and voltage-activated L-type Ca2+ channels, an activating mechanism that is absent in the efferent arteriole. In the efferent arteriole, Ang II stimulates Ca2+ influx through a signaling pathway that is nifedipine-insensitive and is not voltage-activated. Store depletion with CPA activates a nifedipine-insensitive Ca2+ entry in efferent myocytes that has a sensitivity to SKF 96365 identical to that of the Ca2+ influx activated by Ang II in the intact arteriole. This store-operated Ca2+ entry mechanism is absent in the afferent arteriole.. Our findings agree with those of previous studies assessing renal microvascular ...
Purpose: : Hyperglycemia and oxidative stress are implicated in retinal vascular dysfunction associated with the development of diabetic retinopathy. Although retinal arterioles provide a major site of flow regulation, the temporal influence of hyperglycemia on retinal arteriolar reactivity and vascular oxidant production remains unclear. The development of a large animal model of diabetes relevant to the human retina for evaluation of vascular function is also lacking. Herein, we examined endothelium-dependent nitric oxide (NO)-mediated dilation and production of superoxide in retinal arterioles at various time points in a porcine model of type 1 diabetes. Methods: : Retinal arterioles (,100 µm) were isolated from streptozotocin-induced diabetic pigs (2, 6, 10 and 14 weeks of hyperglycemia, 477±43 mg/dL) and age-matched control pigs (63±14 mg/dL), and then cannulated and pressurized for in vitro study. Vascular diameter changes and superoxide production were monitored using videomicroscopic ...
Parenchymal arterioles (PAs) are high-resistance vessels in the brain that connect pial vessels to the microcirculation. We previously showed that PAs have increased vasoconstriction after ischemia and reperfusion that could increase perfusion defici
TY - JOUR. T1 - KV 7.4 channels participate in the control of rodent renal vascular resting tone.. AU - Salomonsson, M.. AU - Brasen, Jens Christian. AU - Braunstein, Thomas Hartig. AU - Hagelqvist, Per Gustav. AU - Holstein-Rathlou, N.-H. PY - 2015. Y1 - 2015. N2 - Aim: We tested the hypothesis that KV7 channels contribute to basal renal vascular tone and that they participate in agonist-induced renal vasoconstriction or vasodilation. Methods: KV7 channel subtypes in renal arterioles were characterized by immunofluorescence. Renal blood flow (RBF) was measured using an ultrasonic flow probe. The isometric tension of rat interlobar arteries was examined in a wire myograph. Mice afferent arteriolar diameter was assessed utilizing the perfused juxtamedullary nephron technique. Results: Immunofluorescence revealed that KV7.4 channels were expressed in rat afferent arterioles. The KV7 blocker XE991 dose-dependently increased the isometric tension of rat interlobar arteries and caused a small ...
PubMed journal article: Regulation of angiotensin II receptor AT1 subtypes in renal afferent arterioles during chronic changes in sodium diet. Download Prime PubMed App to iPhone, iPad, or Android
Flow-induced dilation of human coronary arterioles (HCA) is mediated by a unique mechanism involving the release of H2O2 from the mitochondria of endothelial cells and subsequent smooth muscle relaxation via K+-channel-dependent membrane hyperpolarization. The precise mechanisms by which H2O2 induces smooth muscle hyperpolarization remain largely undefined. An important mechanism of action of H2O2 involves the oxidation of key cysteine residues in its target proteins, including protein kinase G 1-alpha (PKG-1α). Here we hypothesize that H2O2 dilates HCA through direct oxidation and activation of PKG-1α leading to the subsequent opening of large-conductance Ca2+-activated K+ channels (BKCa) in smooth muscle cells. In isolated HCA, H2O2 (10−6−3×10−4 M) induced dose-dependent dilations in both endothelium-intact and -denuded vessels (relaxations at 10−4 M of 83.5±3.7% and 85.1±8.4%, respectively; n=4 - 6). The relaxations were largely abolished by iberiotoxin, a BKCa blocker (3.4±2.1% ...
We used a lung slice preparation to study the contractile responses of intrapulmonary arterioles and the underlying changes in [Ca2+]i in their SMCs during stimulation with 5-HT and KCl. For the same reasons that apply to the study of bronchial airways (Bergner and Sanderson, 2002a), thin lung slices are well suited for the study of arterioles. The arterioles are easily identified, have reproducible contractile responses and the intracellular Ca2+ responses of their SMCs can be correlated with the contraction of the arteriole. In addition, the small intrapulmonary arterioles, at sites that are considered to be important in pulmonary hypertension, can be examined. A major advantage of the lung slice is the ability to simultaneously compare the responses of arteriole SMCs to those of airway SMCs. This allows for the instant collection of control data and facilitates an understanding of the specific physiological responses of each SMC type.. Vasoconstriction of pulmonary arteries to 5-HT has been ...
It is typical in microvascular networks for smaller vessels to have lower linear blood velocities (38, 67). Application of a LEA instrument to vessels with velocities below Vcr = 2,100 μm/s creates a progressive Po2 underestimation from large arterioles to capillaries due to an increase in the accumulated oxygen consumption with the decrease in velocity. In addition, a LEA instrument depresses Po2 in the perivascular tissue (16), thereby creating a greater oxygen sink, which adds to the diffusional oxygen losses from arterioles and amplifies the apparent longitudinal Po2 gradient. Previous workers have concluded that this apparent longitudinal Po2 gradient found in precapillary arterioles is due to high oxygen losses from the arterioles, which led them to further conclude that arterioles are the main site of oxygen supply to the tissue (52-54, 56).. In the study of Tsai et al. (54), the longitudinal oxygen saturation drop in mesenteric arterioles with an average diameter of 23 μm was estimated ...
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A Human Arteriole Cross-Section. Arterioles are Small Branches of Arteries Photographic Print by Robert Caughey - at AllPosters.com. Choose from over 500,000 Posters & Art Prints. Value Framing, Fast Delivery, 100% Satisfaction Guarantee.
Renal preglomerular arterioles regulate vascular tone to ensure a large pressure gradient over short distances, a function that is extremely important for maintaining renal microcirculation. Regulation of renal microvascular tone is impaired in salt-sensitive (SS) hypertension-induced nephropathy, but the molecular mechanisms contributing to this impairment remain elusive. Here, we assessed the contribution of the SH2 adaptor protein p66Shc (encoded by Shc1) in regulating renal vascular tone and the development of renal vascular dysfunction associated with hypertension-induced nephropathy. We generated a panel of mutant rat strains in which specific modifications of Shc1 were introduced into the Dahl SS rats. In SS rats, overexpression of p66Shc was linked to increased renal damage. Conversely, deletion of p66Shc from these rats restored the myogenic responsiveness of renal preglomerular arterioles ex vivo and promoted cellular contraction in primary vascular smooth muscle cells (SMCs) that were ...
We have formulated a mathematical model for the rat afferent arteriole (AA). Our model consists of a series of arteriolar smooth muscle cells and endothelial cells, each of which represents ion transport, cell membrane potential, and gap junction coupling. Cellular contraction and wall mechanics are also represented for the smooth muscle cells. Blood flow through the AA lumen is described by Poiseuille flow. The AA models representation of the myogenic response is based on the hypothesis that changes in hydrostatic pressure induce changes in the activity of nonselective cation channels. The resulting changes in membrane potential then affect calcium influx through changes in the activity of the voltage-gated calcium channels, so that vessel diameter decreases with increasing pressure values. With this configuration, the model AA maintains roughly stable renal blood flow within a physiologic range of blood flow pressure. Model simulation of vasoconstriction initiated from local stimulation also ...
TY - JOUR. T1 - Preserved coronary arteriolar dilatation in patients with type 2 diabetes mellitus. T2 - Implications for reactive oxygen species. AU - Bagi, Zsolt. AU - Feher, Attila. AU - Beleznai, Timea. PY - 2009/1/1. Y1 - 2009/1/1. N2 - Type 2 diabetes mellitus is associated with clustering of cardiovascular risk factors that may greatly increase individuals risk of developing coronary artery disease. Type 2 diabetes is believed to impair coronary function. However, its impact on the vasomotor function of coronary resistance vessels in humans is still debated. Reduced, preserved or even augmented dilations of coronary arterioles have been reported in subjects with type 2 diabetes. Interestingly, recent studies have suggested that reactive oxygen species (ROS), particularly hydrogen peroxide, may compensate for the loss of the vasodilatory function of coronary microvessels during disease development. Recent interventional clinical trials have yielded largely negative results, and there has ...
Aging with oxidant stress is a major risk factor of coronary artery disease, however the underlying mechanisms have not been fully defined. Senescence marker protein 30 (SMP30) has been identified as an aging marker molecule, which decreases with aging and SMP 30 knock-out mice show a short life. To examine the effect of aging on coronary arterioles vasomotor tone, we measured endothelium-dependent (acetylcholine, ACh) and -independent vasodilation (sodium nitroprusside, SNP) of isolated, pressurized coronary arterioles (28±4 µm, diameter) from SMP30 KO and wild type (WT) mice. In SMP30 KO mice, ACh-induced vasoconstriction was appeared, which changed vasodilation with dithiothreitol, thiol-reducing agent (DTT, 0.1 µM), but L-NAME (0.3 mM) or sepiapterin (1 µM), tetrahydrobiopterin mimic, did not change vascular responses to ACh. In WT mice, ACh-induced vasodilation was appeared which was blunted with L-NAME. Inhibition of glutathione reductase by 1, 3-bis (2-chloroethyl)-1-nitrosourea (80 ...
Role of the Afferent and Efferent Arterioles The kidneys have an autoregulatory system to keep their blood flow and perfusion constant over a wide range of blood pressures. Unlike perfusion of all other organs, perfusion of the kidney is not regulated to maintain organ nutrition but to retain its filtration functions. The glomerular hydrostatic pressure is regulated mainly by the balance of vascular tone in the afferent and efferent arterioles. Owing to this exceptional arrangement of resistance vessels in series, before and after the glomerulus, renal blood flow (RBF) and glomerular filtration rate (GFR) can be regulated independently.
We transplanted neonatal hamster renal tissue into a hamster check pouch chamber and subjected the renal tissue to increases and decreases in extravascular pressure. A decrease in extra-vascular pressure decreased, and an increase in extravascular pressure increased, the diameter of preglomerular arterioles. Thus, the change in preglomerular arteriolar diameter was directly related to alterations in extravascular pressure. Neither saralasin nor indomethacin affected these changes, whereas papaverin prevented them. The efferen arterioles responded passively to changes in extravascular pressure; i.e., the changes in their diameter were inversely related to changes in extravascular myogenic autoregulation of preglomerular vessels. ...
The efferent arteriole carries blood away from the glomerulus. Because it has a smaller diameter than the afferent arteriole, it creates some resistance to blood flow, producing the back-up of blood in the glomerulus which creates higher pressure in the glomerular cavity.. ...
The transient receptor potential type V1 channel (vanilloid receptor 1, TRPV1) is a Ca2+-permeable nonspecific cation channel activated by various painful stimuli including ischemia. We hypothesized that TRPV1 is expressed in the arterioles and is involved in the regulation of microvascular tone. We found that TRPV1 stimulation by capsaicin (intra-arterial administration) of the isolated, perfused right hind limb of the rat increased vascular resistance (by 98 ± 21 mm Hg at 10 μg) in association with decreased skeletal muscle perfusion and elevation of skin perfusion (detected by dual-channel laser Doppler flowmetry). Denervation of the hind limb did not affect capsaicin-evoked changes in vascular resistance and tissue perfusion in the hind limb but reduced the elevation of perfusion in the skin. In isolated, pressurized skeletal (musculus gracilis) muscle arterioles (diameter, 147 ± 35 μm), capsaicin had biphasic effects: at lower concentrations, capsaicin (up to 10 nM) evoked dilations ...
Arteriole. Light micrograph of a section through an arteriole, a small artery. The lumen (centre) of the arteriole is filled with red blood cells. The lumen is lined by a single layer of epithelial cells, which are surrounded by a ring of smooth muscle (purple). Outside of this is elastic and collagen connective tissue (brown). Magnification: x250 when printed at 10 centimetres wide. Human tissue. - Stock Image C019/8018
Chemical: Noradrenaline constricts interlobular and afferent arterioles. Angiotensin 11 constricts efferent arterioles , afferent arterioles. Dopamine (made in kidney) vasodilates. Acetylcholine vasodilates. Prostaglandins inc. bl flow in cortex, dec. bl flow in medulla.. - Neural: SNS -, dec bl flow. Fall of BP, vasoconstrictor response includes renal bl flow.. - Autoregulation: contractile response of smooth muscle of afferent arteriole to stretch (BP). NO may be involved. Angiotensin 11 plays a role in constricting efferent arterioles, maintaining GFR,. ...
Guarda Foto stock di Red And White Blood Cells Within An Arteriole Arteries Branch Into Arterioles Within Organs And Deliver Blood To The Capillaries Sem X6130. Cerca foto premium ad alta risoluzione su Getty Images.
An increase in glomerular filtration rate (GFR) in early diabetes mellitus is considered a risk factor for the development of diabetic nephropathy. Insulin deficiency may increase the activity of ATP-sensitive potassium channels (KATP), which could promote afferent arteriolar vasodilation und thus contribute to glomerular hyperfiltration in early diabetes mellitus. To further elucidate this hypothesis we performed renal clearance experiments in anesthetized rats at 2 and 6 weeks after onset of streptozotocin-induced insulin-treated diabetes mellitus and studied the acute effect of the putative KATP channel blocker 4-morpholinecarboximidine-N-1-adamantyl-N′-cyclohexylhydrochloride (U37883A) on renal function. In control rats, application of U37883A (1.5 mg/kg i.v. bolus plus 1.5 mg/kg/hr) induced a significant reduction in heart rate, but did not affect or even slightly increased mean arterial blood pressure. Furthermore, U37883A did not significantly affect renal vascular resistance, renal ...
The purpose of our study was to determine whether Gi-mediated control over adenylyl cyclase in preglomerular arteriolar smooth muscle cells (PGASMC) is enhanced in the spontaneously hypertensive rat (SHR). PGASMC were cultured from preglomerular microvessels isolated from adult SHR (14-15 wk of age) and age-matched WKY rats. Confluent monolayers of cells in third passage were used for the experiments. cAMP released into the media (30 min) as well as cellular levels of cAMP were measured in the presence of a phosphodiesterase inhibitor, 1-isobutyl-3-methyl-xanthine (IBMX; 100 μM) and expressed as pmol/mg protein. Total (released + cellular) cAMP was significantly lower in SHR (14.19 ± 2.30 pmol/mg protein) as compared with WKY (28.3 ± 3.04 pmol/mg protein). Correspondingly, the released (4.6 ± 0.4 pmol/mg protein) as well as cellular (9.78 ± 2.18 pmol/mg protein) cAMP levels were also significantly lower in SHR when compared with WKY (8.85 ± 1.26 and 18.86 ± 2.0 pmol/mg protein, ...
What is the difference between Arteries and Arterioles? Arteries and arterioles are two types of blood vessels that mainly carry oxygenated blood. Arteries
10 μm) the PD cases have fewer capillaries in the RN and more small arterioles/veins (in the LC) with a significant reduction in the ratio of small/large vessels throughout all nuclei. The data suggest that vessel degeneration in PD cases is primarily at the level of capillaries, that may be more vulnerable to degeneration than the small arteries/veins, and/or to the enlarged capillaries as a result of vascular remodelling [6]. The transformation of the microvasculature from primarily capillaries to predominantly small arterioles/venules has a profound effect on oxygen diffusion. Arterioles (and venules) are much larger vessels with, on average, 3 layers of endothelial cells as well as smooth muscle cells and pericytes [7]. In normal tissue the majority of oxygen diffusion occurs from the capillary vessels consisting of only one layer of endothelial cells [7]. As a consequence of the loss of the capillary bed, tissues receive less oxygen leading to damage through processes such as the ...
Despite latest advances in our understanding of the molecular and mobile mechanisms behind vascular conducted responses (VCRs) in systemic arterioles, we even now know hardly any about their potential physiological and pathophysiological part in brain penetrating arterioles controlling blood circulation to the deeper areas of the brain. of VCRs, which is a rather new finding in this field, is discussed in the light of changes in plasma membrane ion channel conductance as a function of health status or disease. Finally, we discuss the possible role of VCRs in cerebrovascular function and disease as well as suggest future directions for studying VCRs in the cerebral circulation. were recently reported using a transgenic mouse expressing a GCamP2 Ca2+ sensor under the control of a Cx40 promotor found only in ECs of the vasculature and Purkinje fibers of the heart.16 Finally, sharp microelectrode measurements of models are routinely performed in only a few laboratories.10, 32, 34, 35 Molecular and ...
Prostaglandin F2α constricted pial arterioles when locally applied to the cerebral surface. Norepinephrine and serotonin each elicited similar contractile effects. The constriction produced by F2α in combination with either biogenic amine was greater than the constriction elicited by F2α or amine acting alone. The effect of one agent on the other was additive rather than potentiating. Since F2α, norepinephrine and serotonin are all naturally occurring agents, it is possible that their combined effect is important under pathological circumstances and this combined effect should not be overlooked in the search for single spasmogens of great potency. Before ascribing a pathologically important effect to F2α, either alone or in combination, evidence is required showing that doses effective in experiments are similar to the concentrations occurring during disease states and/or that vessels may become hypersensitive to F2α during such states.. ...
TY - JOUR. T1 - Tissue PO2 and arteriolar responses to metabolic stimuli during maturation of striated muscle. AU - Proctor, K. G.. AU - Damon, D. N.. AU - Duling, B. R.. PY - 1981. Y1 - 1981. N2 - Tissue O2 tension (PO2) and small arteriolar diameter were measured in hamsters aged 32, 60, and 80 days. The cremaster muscle was isolated and superfused with a solution equilibrated with 0, 5, or 10% O2 and stimulated to contract at 1 Hz. Resting muscle tissue PO2 was proportional to superfusate PO2 and was not different between age groups. The decrease in tissue PO2 during contraction was greatest in adult animals when the superfusate PO2 was low but was equal in all groups when the superfusate PO2 was high. Elevated superfusate PO2 was correlated with a vasoconstriction, the magnitude of which varied inversely with age. Resting and contraction-induced vascular diameter were largest in the youngest animals, relative to maximum diameters, but absolute resting and contraction-induced diameters were ...
A number of possible explanations may account for the differences between the effects of soluble and insoluble integrin ligands on Ca2+ channel current. An obvious possibility is that inhibition of current by soluble FN may be mediated by competitive antagonism of existing integrin- matrix interactions, as suggested for other systems (Poole and Watson, 1995). This would require constitutive phosphorylation of the channel through an integrin-dependent pathway. Indeed, the L-type calcium channel in vascular smooth muscle has been shown to require tyrosine phosphorylation for normal function (Wijetunge et al., 1992; Wijetunge and Hughes, 1996), but whether integrins regulate this pathway is not known. If they do, then disruption of existing integrin-matrix interactions by soluble ligands would produce inhibition of current while clustering of receptors by insoluble ligands (Altieri et al., 1990; Schwartz, 1993), including antibodies (Miyamoto et al., 1995a), would produce enhancement of current. In ...
Diastolic BP rose and cardiac output diminished after 6 months of exercises training because of the increase in peripheral resistance of blood vessels in athletes. In result of the training, skeletal muscles became capable of a profound relaxation leading, in its turn, to development of the ability for marked constriction of skeletal muscles arterioles. After the exercises, the rigidity of femoral and tibial arteries decreased as the result of involvement of the artery walls smooth muscle cells into peripheral vasodilatation. The functional condition of the skeletal muscles arterioles seems to be the main factor affecting circulatory changes both during acute effect of exercise and after a prolonged training.
Now let us see how the above factors control the distribution of blood flow in physiological situations. The structures that normally have the largest changes in blood flow are the skin, the digestive tract and skeletal muscle.. SKIN: Blood flow to the skin is almost entirely for the purposes of thermoregulation. Very little of the total is required to support the metabolism of the skin cells. Heat is carried by the blood from inside the body to the skin, where it is lost to the atmosphere. Most heat is lost this way, with the only other significant loss of heat occurring through breathing. Sympathetic nerves control the skin arterioles for this purpose, with greater release of norepinephrine causing vasoconstriction. Since under neutral conditions there is some steady sympathetic activity to the skin, reduction of the sympathetic effects allows vasodilation. Unlike many structures, arterioles do not have the dual innervation by both sympathetic and parasympathetic nerves.. DIGESTIVE TRACT: As ...
An arteriole is a blood vessel that extends and branches out from an artery and leads to capillaries. Arterioles have thick muscular walls and are the primary site of vascular resistance. The mean blood pressure in the arteries supplying the body is a result of the interaction between the cardiac output (the volume of blood the heart is pumping per minute) and the vascular resistance, usually termed total peripheral resistance by physicians and researchers. The up and down fluctuation of the arterial blood pressure is due to the pulsatile nature of the cardiac output and determined by the interaction of the stroke volume versus the volume and elasticity of the major arteries. Template:Anatomy-stub ...
Acute stroke induces a local inflammatory reaction causing leukocyte infiltration. Circulating monocytes are recruited to the ischemic brain and become tissue macrophages morphologically indistinguishable from reactive microglia. However, monocytes are a heterogeneous population of cells with different functions. Herein, we investigated the infiltration and fate of the monocyte subsets in a mouse model of focal brain ischemia by permanent occlusion of the distal portion of the middle cerebral artery. We separated two main subtypes of CD11bhi monocytes according to their expression of the surface markers Ly6C and CD43. Using adoptive transfer of reporter monocytes and monocyte depletion, we identified the pro-inflammatory Ly6ChiCD43loCCR2+ subset as the predominant monocytes recruited to the ischemic tissue. Monocytes were seen in the leptomeninges from where they entered the cortex along the penetrating arterioles. Four days post-ischemia, they had invaded the infarcted core, where they were often
Arteriole. Coloured transmission electron micrograph (TEM) of a section through the wall of an arteriole, showing smooth muscle (brown), endothelial cells (green), and an inner and outer lamina (membrane, blue). Elastic and collagen connective tissue (clear) can also be seen, along with pinocytotic vesicles.. Magnification: x20,000 when printed 10 centimetres wide. - Stock Image C011/9459
The brain is critically dependent on the regulation of blood flow to nourish active neurons. One widely held hypothesis of blood flow regulation holds that active neurons stimulate Ca(2+) increases in glial cells, triggering glial release of vasodilating agents. This hypothesis has been challenged, as arteriole dilation can occur in the absence of glial Ca(2+) signaling. We address this controversy by imaging glial Ca(2+) signaling and vessel dilation in the mouse retina. We find that sensory stimulation results in Ca(2+) increases in the glial endfeet contacting capillaries, but not arterioles, and that capillary dilations often follow spontaneous Ca(2+) signaling. In IP3R2(-/-) mice, where glial Ca(2+) signaling is reduced, light-evoked capillary, but not arteriole, dilation is abolished. The results show that, independent of arterioles, capillaries actively dilate and regulate blood flow. Furthermore, the results demonstrate that glial Ca(2+) signaling regulates capillary but not arteriole ...
The brain is critically dependent on the regulation of blood flow to nourish active neurons. One widely held hypothesis of blood flow regulation holds that active neurons stimulate Ca(2+) increases in glial cells, triggering glial release of vasodilating agents. This hypothesis has been challenged, as arteriole dilation can occur in the absence of glial Ca(2+) signaling. We address this controversy by imaging glial Ca(2+) signaling and vessel dilation in the mouse retina. We find that sensory stimulation results in Ca(2+) increases in the glial endfeet contacting capillaries, but not arterioles, and that capillary dilations often follow spontaneous Ca(2+) signaling. In IP3R2(-/-) mice, where glial Ca(2+) signaling is reduced, light-evoked capillary, but not arteriole, dilation is abolished. The results show that, independent of arterioles, capillaries actively dilate and regulate blood flow. Furthermore, the results demonstrate that glial Ca(2+) signaling regulates capillary but not arteriole ...
The major findings in newborn pigs are: (1) treatment with the astrocyte toxin, L-2αAAA, or the HO inhibitor, CrMP, block pial arteriolar dilation to ADP, but not to isoproterenol, bradykinin, or sodium nitroprusside; (2) ADP increases brain CO production and this increase is blocked by the astrocyte toxin or inhibition of HO; and (3) ADP increases CO production by astrocytes and, to a lesser extent, cerebral microvessels. These data, coupled with previous results showing CO dilates pial arterioles in vivo, suggest CO is an astrocyte-derived mediator of ADP-induced pial arteriolar dilation in piglets.. ADP can produce endothelium-dependent cerebral vasodilation,19 which may be mediated in part by NO and endothelium-derived hyperpolarizing factor in adult rats.20,21,30 In endothelium-denuded control arteries from rat brain, ADP also produced dose-dependent relaxation, but this relaxation was lower than that found in intact control arteries.31 In adult rats, ADP-induced pial arteriolar dilation ...
TY - JOUR. T1 - Interaction between ATP-sensitive K+ channels and nitric oxide on pial arterioles in piglets. AU - Bari, F.. AU - Errico, Robert A.. AU - Louis, Thomas M.. AU - Busija, David W.. PY - 1996. Y1 - 1996. N2 - The interaction between ATP-sensitive K+ channels (K(ATP)) and nitric oxide (NO) was studied in pial arterioles of piglets. We examined the effects of N(ω)-nitro-L-arginine methyl ester (L-NAME), a general inhibitor of nitric oxide synthase (NOS), and 7-nitroindazole (7-NI), a selective inhibitor of neuronal NOS, on aprikalim-induced cerebral vasodilation. Topically applied, aprikalim, a selective activator of K(ATP), dilated arterioles by 11 ± 7% at 10-8 M and 17 ± 6% at 10-6 M. After L-NAME treatment (15 mg/kg, i.v.), the response was reduced (4 ± 4% and 12 ± 7%, respectively; n = 8, p ,0.05). Administration of 7-NI (50 mg/kg, i.p.) did not change pial arteriolar responsiveness to aprikalim. However, both L-NAME and 7-NI reduced the vasodilator responses to 10-4 M ...
TY - JOUR. T1 - Responses of cerebral arterioles during chronic ethanol exposure. AU - Mayhan, William. PY - 1992. Y1 - 1992. N2 - The purpose of this study was to examine the effects of ethanol exposure on responses of cerebral arterioles in vivo. Rats were fed liquid diets with or without ethanol for 2-3 mo. Using intravital microscopy, we measured diameter of cerebral arterioles in non-ethanol- and ethanol-fed rats in response to acetylcholine, histamine, ADP, the thromboxane analogue (U- 46619), and nitroglycerin. In non-ethanol-fed rats, acetylcholine, histamine, and ADP produced dose-related dilatation of cerebral arterioles. In ethanol- fed rats, however, acetylcholine produced vasoconstriction, and vasodilatation in response to histamine and ADP was impaired. Dilatation of cerebral arterioles in response to nitroglycerin and vasoconstriction in response to the thromboxane analogue (U-46619) were similar in non-ethanol- fed and ethanol-fed rats. Thus these findings suggest that chronic ...
Subarachnoid hemorrhage (SAH) following cerebral aneurysm rupture is associated with substantial morbidity and mortality. The ability of SAH to induce vasospasm in large diameter pial arteries has been extensively studied, although the contribution of this phenomenon to patient outcome is unclear. Conversely, little is known regarding the impact of SAH on intracerebral (parenchymal) arterioles, which are critical for regulation of cerebral blood flow. To assess the function of parenchymal arterioles following SAH, measurements of diameter, intracellular Ca2+ ([Ca2+]i) and membrane potential were performed in intact arterioles from unoperated (control), sham-operated and SAH model rats. At physiological intravascular pressure, parenchymal arterioles from SAH animals exhibited significantly elevated [Ca2+]i and enhanced constriction compared with arterioles from control and sham-operated animals. Elevated [Ca2+]i and enhanced tone following SAH were observed in the absence of vascular endothelium and were
Blood flow partitioning at an arteriolar bifurcation could lead to spatio-temporal variations in cell-free layer formation in the upstream and downstream vessels of the bifurcation. To investigate this effect, we quantitatively analyzed characteristics of the cell-free layer in the vicinity of an arteriolar bifurcation in the rat cremaster muscle in normal physiological flow conditions. To simulate hemorheological relevance to humans, red blood cell aggregation was elevated by infusion of Dextran 500 to levels seen in humans in normal states. Spatial variations of the layer width were observed in both the parent and larger daughter vessels. A more pronounced attenuation of the layer width was generally observed in the parent vessel at its wall adjacent to the side branch than at its opposite wall. A thicker layer width was consistently found at the opposite than adjacent wall of the larger daughter vessel. Accordingly, large asymmetries of the layer widths could be developed on opposite sides of ...
The vascular myogenic response is characterized by arterial constriction in response to an increase in intraluminal pressure and dilatation to a decrease in pressure. This mechanism is important for the regulation of blood flow, capillary pressure and arterial pressure. The identity of the mechanosensory mechanism(s) for this response is incompletely understood but has been shown to include the integrins as cell-extracellular matrix receptors. The possibility that a cell-cell adhesion receptor is involved has not been studied. Thus, we tested the hypothesis that N-cadherin, a cell-cell adhesion molecule in vascular smooth muscle cells (VSMCs), was important for myogenic responsiveness. The purpose of this study was to investigate:1. whether cadherin inhibition blocks myogenic responses to increases in intraluminal pressure and 2. the effect of the cadherin or integrin blockade on pressure-induced changes in [Ca2+]i. Cadherin blockade was tested in isolated rat cremaster arterioles on myogenic
Looking for afferent glomerular arteriole? Find out information about afferent glomerular arteriole. An artery of small diameter that terminates in capillaries Explanation of afferent glomerular arteriole
In response to Dr. Grutzendlers comments, we would like to emphasize that two recent exceptional papers (Mishra et al., 2016; Biesecker et al., 2016) from two different groups have independently confirmed the role of pericytes in neurovascular coupling, as we also showed. These two papers demonstrated that astrocytic calcium regulates neurovascular coupling to pericytes, but not to arteriolar smooth muscle cells. Moreover, a recent single-cell RNA-seq study demonstrated expression of several contractile proteins in pericytes derived from mouse cortex or hippocampus including skeletal muscle actin, vimentin, desmin, calponin, non-muscle myosin variants, and a low SMA (smooth muscle actin) expression (Zeisel et al., 2015). This study confirmed earlier findings showing expression of contractile proteins in pericytes using immunocytochemical staining and immunogold labeling at the ultrastructural level. Additionally, two recent optogenetic studies, both presented at the Society for Neuroscience ...
The apparatus was transferred to an inverted microscope (Nikon TMS-F, 20× objective, Nikon, Melville, NY). Steady-state measurements of internal diameter at the midpoint of the segment were made using a high resolution CCD video camera (Hitachi KPC503, Hitachi, San Jose, CA) and a video caliper (Living Systems) calibrated using a stage micrometer. The vessel was superfused with PSS at a rate of 6 ml/min, and the chamber was maintained at 37°C. Chamber temperature and pH were monitored continuously using a probe (Oakton, series 35616, Singapore), and samples of the superfusing buffer were periodically drawn from the chamber for gas analysis (AVL Instruments, model 995, Graz, Austria). A plexiglas cover excluded ambient air from the chamber. The reservoir containing the perfusate and superfusate and the vessel chamber itself were bubbled with gas whose composition was adjusted, using separate tanks and regulators for each of oxygen, carbon dioxide, and nitrogen, to achieve Po2and Pco2values in ...
The efferent arterioles of the juxtamedullary glomeruli are much different. They do break up, but they form bundles of vessels (arteriolae recti) that cross the outer zone of the medulla to perfuse the inner zone. Vessels returning from the inner medulla (venulae recti) intersperse themselves in a highly regular fashion among the descending arteriolae recti to form a well-organized rete mirabile. This rete is responsible for the osmotic isolation of the inner medulla from the rest of the kidney and so permits the excretion of a hypertonic urine when circumstances require. Since the rete also isolates the inner medulla from gaseous exchange, any metabolism in this area is anaerobic, and red cells, which would serve no purpose there, are ordinarily shunted from the arteriolae recti by an unknown mechanism into the capillary plexus surrounding the tubules of the outer zone of the medulla. Blood in this plexus and returning from the inner medulla finds its way to the renal vein and the general ...
Previously, we found increased expression of l-arginine metabolizing enzymes in both kidneys from two-kidney, one-clip (2K1C) hypertensive rats (Helle F, Hultstrom M, Skogstrand T, Palm F, Iversen BM. Am J Physiol Renal Physiol 296: F78-F86, 2009). In the present study, we investigate whether AT(1) receptor activation can induce the changes observed in 2K1C. Four groups of rats were infused with 80 ng/min ANG II or saline for 14 days and/or given 60 mg x kg(-1) x day(-1) losartan. Gene expression was studied in isolated preglomerular vessels by RT-PCR. Dose-responses to ANG II were studied in isolated preglomerular vessels with and without acute NOS inhibition [10(-4) mol/l N(G)-nitro-l-arginine methyl ester (l-NAME)]. Expressions of endothelial nitric oxide synthase (eNOS), caveolin-1, and arginase-2 were not changed by ANG II infusion. CAT1 (0.3 8 +/- 0.07 to 0.73 +/- 0.12, P , 0.05), CAT2 (1.14 +/- 0.29 to 2.74 +/- 0.48), DDAH2 (1.09 +/- 0.27 to 2.3 +/- 0.46), and arginase-1 (1.08 +/- 0.17 to ...
Beginning in small radicals around the base of the alveoli, venules are formed through the coalescence of capillaries. These rapidly converge to a. point near the terminal arterioles about the intercalary duct to form venae terminales. The veins are short and there is but a single one accompanying each terminal arteriole. At the point of junction of several intercalary ducts, the accompanying terminal veins through their confluence form the intralobular veins which collect the blood from different portions of the lobule and terminate in the lobular vein. This vessel makes its exit from the lobule at the hilus, side by side with the lobular artery. There is no reduplication of the veins of the intralobular system. As soon as the veins leave the lobules, however, and enter the sublobular interspaces, the venous system is doubled, yielding venae comites to each successive division of the A. submaxillaris. The sublobular veins parallel the course of the artery, giving ofi numerous anastomotic ...
Signs and Symptoms. Retinal arterial macroaneurysms (RAM) are acquired saccular or fusiform dilatations of the large arterioles of the retina.1-7 They are usually observed within the first three orders of bifurcation and can occur at arteriovenous crossings as well.4,7 Patients who develop RAM are typically between the ages of 50 and 80.1-7 They rarely occur in younger patients, but when they do the most consistently associated systemic disease is hypertension.7 There appears to be a female preponderance.4-6 The most common comorbidity is systemic arterial hypertension, occurring in approximately 80% of patients.1-7 There is also an increased incidence of cardiovascular disease and arteriosclerosis.5,6 Ophthalmoscopically, RAM appear as an exudative, dilated arteriole within a major vascular branch within the first three bifurcations.1-9 In rare circumstances, they can occur just off of the optic disc.10 RAM are typically unilateral, but may be bilateral or multifocal.3,5 In many cases, ...
High blood pressure is the leading risk factor for death worldwide. One of the hallmarks is a rise of peripheral vascular resistance, which largely depends on arteriole tone. Ca2+-activated chloride currents (CaCCs) in vascular smooth muscle cells (VSMCs) are candidates for increasing vascular contractility. We analyzed the vascular tree and identified substantial CaCCs in VSMCs of the aorta and carotid arteries. CaCCs were small or absent in VSMCs of medium-sized vessels such as mesenteric arteries and larger retinal arterioles. In small vessels of the retina, brain, and skeletal muscle, where contractile intermediate cells or pericytes gradually replace VSMCs, CaCCs were particularly large. Targeted disruption of the calcium-activated chloride channel TMEM16A, also known as ANO1, in VSMCs, intermediate cells, and pericytes eliminated CaCCs in all vessels studied. Mice lacking vascular TMEM16A had lower systemic blood pressure and a decreased hypertensive response following vasoconstrictor ...
TY - JOUR. T1 - Smoke Movement and Evacuation Time in the Arcade of a Traditional Market using Numerical Simulation. AU - Kim, Taeyeon. AU - Kim, Byungseon Sean. AU - Kim, Kwangho. PY - 2007. Y1 - 2007. N2 - This study proposes to analyze the smoke exhausting performance and evacuation time in an arcade of a Korean traditional market. The effect of three types of ventilation opening on smoke exhausting performance was analyzed using the CFD (Computational Fluid Dynamics) method. The ventilation opening delayed the spread of smoke efficiently, and is an important design factor to control smoke movement in arcades. Also the evacuation time was analyzed according to the height of the building and increased significantly with the increase in the number of floors. Given the conditions of the study, the arcade building had to be less than three-stories considering the spread of smoke.. AB - This study proposes to analyze the smoke exhausting performance and evacuation time in an arcade of a Korean ...
Nitroglycerin is, at typical doses, a VENOUS dilator. By decreasing venous return to the heart (preload) nitroglycerin decreases the filling pressure of the heart, decreasing myocardial wall tension, force of contraction, and by extension, myocardial workload and oxygen demand of the stressed tissue. Nitroglycerin only minor effect on arteries or arterioles at usual doses, although a high dose drip (greater than 40mcg/min) can have artery dilating effects. So, nitro does not dilate atherosclerotic arteries to allow blood to flow around any clots or occlusions in the arterial system of the heart. When nitroglycerin has been injected directly into a blocked coronary artery, it has not relieved pain! In other words, nitroglycerin eases coronary chest pain by reducing the hearts oxygen needs, NOT by providing more oxygen supply. Although blood pressure can drop with nitroglycerin, it can be minimized with the patient lying down ...
Coloured Tem Of Red Blood Cells In An Arteriole Poster by Steve Gschmeissner. All posters are professionally printed, packaged, and shipped within 3 - 4 business days. Choose from multiple sizes and hundreds of frame and mat options.
Definition of capillary arteriole. Provided by Stedmans medical dictionary and Drugs.com. Includes medical terms and definitions.
Study finds that arterioles in the palms of fibromyalgia patients are overly dilated, which causes over-sensitization of the nerves, resulting in pa
juxtaglomerular apparatus (JGA) A region of tissue found in each nephron in the kidney that is important is regulating blood pressure and body fluid and electrolytes. … The JGA also includes chemoreceptor cells of the adjacent region of the distal tubule, which form a tightly packed array called the macula densa ...
In one of our earlier attempts to get an official Capcom podcast off the ground, it was me, Brett, and Seth, and the two of them were swapping arcade electrocution stories. I think both involved ill-advised arcade cabinets at their local swimming pools, and I distinctly remember SETH distinctly remembering that when he got shocked, he could feel it all the way in his teeth. Youd think that wouldve been the end of his Street Fighter fascination or at least the end of his swimming fascination, but I have since seen him partake in both. We also had a guest speaker that week, one of the cool dudes in QA, and he was lamenting having recently lost a friend to an arcade cabinet that arced on him while he was tinkering around inside. (Let that be a lesson-those things hold a dangerous charge for awhile even after theyre unplugged). Seemed like everyone had an arcade electrocution story except for me. At the time, I was still quite shy and deferential after so many years in Japan, and I remember ...
Diabetes mellitus, considered at the beginning as a metabolic disorder, mutates into a predominantly vascular disease, once its duration extends over several years or/and when additional cardiovascular (CV) risk factors coexist, in particular arterial hypertension. As a consequence, treatment of type 2 diabetes should focus not only on metabolic control but also on improving the vascular structure and function in the micro- and macrocirculation (1). Glomerular hyperfiltration and hyperperfusion pointing to altered intraglomerular hemodynamics, e.g. reduced preglomerular (i.e. resistance of the afferent arteriole [Ra]) resistance and increased postglomerular (i.e. resistance of the efferent arteriole [Re]) resistance (resulting in an increased intraglomerular pressure [Pglom]) are considered to be pivotal hemodynamic hallmarks of renal impairment in early diabetes (2). Endothelium dysfunction is a key pathogenetic process leading to increased leakage of albumin through the glomerular barrier and ...
Professor Layton is modeling renal function at the level of the nephron (the functional unit of the kidney) and at the level of nephron populations. In particular, he is studying tubuloglomerular feedback (TGF), the urine concentrating mechanism, and the hemodynamics of the afferent arteriole. Dynamic models for TGF and the afferent arteriole involve small systems of semilinear hyperbolic partial differential equations (PDEs) with time-delays, and coupled ODES, which are solved numerically for cases of physiological interest, or which are linearized for qualitative analytical investigation. Dynamic models for the concentrating mechanism involve large systems of coupled hyperbolic PDEs that describe tubular convection and epithelial transport. Numerical solutions of these PDEs help to integrate and interpret quantities determined by physiologists in many separate experiments.. ...
Professor Layton is modeling renal function at the level of the nephron (the functional unit of the kidney) and at the level of nephron populations. In particular, he is studying tubuloglomerular feedback (TGF), the urine concentrating mechanism, and the hemodynamics of the afferent arteriole. Dynamic models for TGF and the afferent arteriole involve small systems of semilinear hyperbolic partial differential equations (PDEs) with time-delays, and coupled ODES, which are solved numerically for cases of physiological interest, or which are linearized for qualitative analytical investigation. Dynamic models for the concentrating mechanism involve large systems of coupled hyperbolic PDEs that describe tubular convection and epithelial transport. Numerical solutions of these PDEs help to integrate and interpret quantities determined by physiologists in many separate experiments. ...
Endothelial cell, Ca2+-activated K channels (SKCa and IKCa channels) generate hyperpolarization that passes to the adjacent vascular smooth muscle cells to cause vasodilation in small resistance arterioles. IKCa channels expressed within endothelial cell projections toward the SMCs are activated by spontaneous Ca2+ events (Ca2+ puffs/pulsars). TRPV4 channels also cluster within this microdomain and are selectively activated at low intravascular pressure resulting in activation of endothelial cell IKCa channels and vasodilation, reducing the myogenic tone that underpins tissue blood-flow autoregulation. ...
Nebulized VasoconstrictorsEpinephrine stimulates alpha receptors and beta2 receptors. It constricts the precapillary arterioles, thus decreasing airway edema. Because of the potential adverse effects ... more
It is a mechanism that can be used to help control [[Blood pressure,blood pressure]]. Vasoconstriction of [[Arterioles,arterioles]] reduces their diameter. This reduction in lumen diameter causes the resistance to [[Blood,blood]] flow to increase as more of the [[Red blood cells,Red Blood Cells]] come into contact with the arteriole walls. This causes blood pressure to increase,ref,Dee Unglaub Silverthorn (2010) Human Physiology An Integrated Approach, Sixth Edition, Glenview: Pearson. Page 519,/ref ...
To tease apart the role of endothelial signaling in the living brain, they had to develop new ways to both image the brain at very high speeds, and also to selectively alter the ability of endothelial cells to propagate signals within intact vessels. The team achieved this through a range of techniques that use light and optics, including imaging using a high-speed camera with synchronized, strobed LED illumination to capture changes in the color, and thus the oxygenation level of flowing blood. Focused laser light was used in combination with a fluorescent dye within the bloodstream to cause oxidative damage to the inner endothelial layer of blood brain arterioles, while leaving the rest of the vessel intact and responsive. The team showed that, after damaging a small section of a vessel using their laser, the vessel no longer dilated beyond the damaged point. When the endothelium of a larger number of vessels was targeted in the same way, the overall blood flow response of the brain to ...
To tease apart the role of endothelial signaling in the living brain, they had to develop new ways to both image the brain at very high speeds, and also to selectively alter the ability of endothelial cells to propagate signals within intact vessels. The team achieved this through a range of techniques that use light and optics, including imaging using a high-speed camera with synchronized, strobed LED illumination to capture changes in the color, and thus the oxygenation level of flowing blood. Focused laser light was used in combination with a fluorescent dye within the bloodstream to cause oxidative damage to the inner endothelial layer of blood brain arterioles, while leaving the rest of the vessel intact and responsive. The team showed that, after damaging a small section of a vessel using their laser, the vessel no longer dilated beyond the damaged point. When the endothelium of a larger number of vessels was targeted in the same way, the overall blood flow response of the brain to ...
Afferent and efferent arterioles (21.5±1.2µm and 15.9±1.2µm diameter), recognised from vascular origins, lead into previously undescribed wider regions (43.2±2.8 µm and 38.4±4.9 µm diameter) we have termed vascular chambers (VCs) embedded in the mesangium of the vascular pole. Afferent VC(AVC) volume was 1.6 fold greater than Efferent VC(EVC) volume. From the AVC long non-branching high capacity conduit vessels (n=7) (Con; 15.9±0.7µm diameter) led to the glomerular edge where branching was more frequent. Conduit vessels have fewer podocytes than filtration capillaries. VCs were confirmed in fixed and unfixed specimens with a layer of banded collagen identified in AVC walls by multiphoton and electron microscopy. Thirteen highly branched efferent first order vessels (E1;9.9±0.4µm diam.) converge on the EVC draining into the efferent arteriole (15.9±1.2µm diam.). Banded collagen was scarce around EVC ...
A dopamine D1 receptor agonist that is used as an antihypertensive agent. It lowers blood pressure through arteriolar vasodilation ...
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An important contributor to local vascular regulation is released by endothelial cells. This substance, endothelium-derived relaxing factor EDRF , is released
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Only a few years ago, console and arcade games were comparable graphically. In fact, it wasnt until the Dreamcast and the amazing Soul Calibur that console games began surpassing the quality offered in an arcade cabinet. Over the past couple of years, weve entered a gaming era where developers feel they must make use of every button on the controller and offer gameplay gimmicks to sell their products. Most Xbox games are the antithesis of the arcade classics, so seeing a good old fashioned shooter come to the box is a delight. However, the problem with porting arcade games to Xbox is that the graphics, sound, and depth rarely translate well. But if not for arcade ports, mindless shoot-em-ups -- where two buttons are all you need to survive -- wouldnt be available to hungry gamers who just want to stay on the couch and not go to the arcade.
There are five types of blood vessels: the arteries, which carry the blood away from the heart; the arterioles; the capillaries ... In general, arteries and arterioles transport oxygenated blood from the lungs to the body and its organs, and veins and venules ... There are various kinds of blood vessels: Arteries Elastic arteries Distributing arteries Arterioles Capillaries (smallest ... Blood is propelled through arteries and arterioles through pressure generated by the heartbeat. Blood vessels also transport ...
Prominent arterioles. Angiolymphatic invasion common. Up to 10-15 mitotic figures per 10 HPF in most active areas. Tongue-like ...
... contraction of arterioles; dilatation of bronchioles; increased levels of blood sugar; sweating; widening of the pupils and ...
Affects capillaries, venules, or arterioles. Thought to be part of a group that includes granulomatosis with polyangiitis since ... Granulomatosis with polyangiitis (GPA). Systemic vasculitis of medium and small arteries, including venules and arterioles. ... or arterioles. Therefore, complement will be low with histology showing vessel inflammation with immune deposits. Vasculitis ...
Dilate arterioles to skeletal muscle. In the normal eye, beta-2 stimulation by salbutamol increases intraocular pressure via ...
There, arterioles control the flow of blood to the capillaries. Arterioles contract and relax, varying their diameter and ... The microvessels include terminal arterioles, metarterioles, capillaries, and venules. Arterioles carry oxygenated blood to the ... Metarterioles connect arterioles and capillaries. A tributary to the venules is known as a thoroughfare channel. The ... Arterioles respond to metabolic stimuli that are generated in the tissues. When tissue metabolism increases, catabolic products ...
As with the arteriole distribution, the veins follow the same pattern: the interlobular provide blood to the arcuate veins then ... Each arcuate artery supplies several interlobular arteries that feed into the afferent arterioles that supply the glomeruli. ... Note 4: The efferent arterioles do not directly drain into the interlobular vein, but rather they go to the peritubular ... The efferent arterioles of the juxtamedullary nephron drain into the vasa recta. ...
Immediately following the arterioles are the capillaries. Following the logic observed in the arterioles, we expect the blood ... This is why[citation needed] the arterioles have the highest pressure-drop. The pressure drop of the arterioles is the product ... In the arterioles blood pressure is lower than in the major arteries. This is due to bifurcations, which cause a drop in ... The high resistance observed in the arterioles, which factor largely in the ∆P is a result of a smaller radius of about 30 µm. ...
"Significance of bright plaques in the retinal arterioles". JAMA. 178: 23-29. doi:10.1001/jama.1961.03040400025005. PMC 1316410 ...
ICD-10-CM Diagnosis Codes > Diseases of the circulatory system (I00-I99) > Diseases of arteries, arterioles and capillaries ( ... ICD-9-CM Diagnosis Codes > Diseases of the circulatory system (390-459) > Diseases of arteries, arterioles, and capillaries ( ...
Hollenhorst RW (1961). "Significance of bright plaques in the retinal arterioles". JAMA. 178: 23-29. doi:10.1001/jama. ...
In some subjects, arterioles and venules can be seen to run parallel with each other. Paired arterioles are generally smaller ... The bulbar conjunctival microvasculature contains arterioles, meta-arterioles, venules, capillaries, and communicating vessels ... Hypertension is associated with an increase in the tortuosity of bulbar conjunctival blood vessels and capillary and arteriole ...
Efferent arterioles appear to play a lesser role; experimental evidence supports both vasoconstriction and vasodilation, with ... The muscle tension in the afferent arteriole is modified based on the difference between the sensed concentration and a target ... Constricting the smooth muscle cells in the afferent arteriole, results in a reduced concentration of chloride at the MD. TGF ... Adenosine constricts the afferent arteriole by binding with high affinity to the A1 receptors a Gi/Go. Adenosine binds with ...
Another determinant of vascular resistance is the pre-capillary arterioles. These arterioles are less than 100 μm in diameter. ... Because resistance is inversely proportional to the fourth power of vessel radius, changes to arteriole diameter can result in ... known as resistance arterioles) tone. These vessels are from 450 μm down to 100 μm in diameter. (As a comparison, the diameter ... but the small arteries and arterioles are the site of about 70% of the pressure drop, and are the main regulators of SVR. When ...
... angiotensin II also constricts the afferent arteriole into the glomerulus in addition to the efferent arteriole it normally ... Prostaglandins normally dilate the afferent arterioles of the glomeruli. This helps maintain normal glomerular perfusion and ... Since NSAIDs block this prostaglandin-mediated effect of afferent arteriole dilation, particularly in kidney failure, NSAIDs ... which removes angiotensin II's vasoconstriction of the efferent arteriole) and a diuretic (which drops plasma volume, and ...
The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow ... This is especially relevant in arterioles of the body. When blood pressure is increased in the blood vessels and the blood ...
... located on the afferent arteriole wall). This leads to renin secretion that causes the angiotensinogen conversion to ...
Hand-warming involves arteriole vasodilation produced by a beta-2 adrenergic hormonal mechanism. Hand-cooling involves ... Skin temperature mainly reflects arteriole diameter. Hand-warming and hand-cooling are produced by separate mechanisms, and ... arteriole vasoconstriction produced by the increased firing of sympathetic C-fibers. Biofeedback therapists use temperature ...
Left heart → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Vena cava → (Right heart) ...
The germinal centers are supplied by arterioles called penicilliary radicles. The spleen is innervated by the splenic plexus, ...
Arteries, arterioles, capillaries, venules, and veins make up the vasculature. The cardiovascular system circulates about 5 ... circulations take the blood through large arteries first and then branches into smaller arteries before reaching arterioles and ...
Human arteries or arterioles that are around 0.2 mm or smaller contribute to creation of the blood flow resistance and are ... Resistance arteries are usually arterioles or end-points of arteries. Having thick muscular walls and narrow lumen they ... arterioles, pre- and postcapillaries. Metabolic vessels - capillaries Capacitance vessels - veins Particular feature of ... Arteriole Cardiovascular Physiology By William R. Milnor. ...
The occluded arterioles can be seen as dark red lines. They eventually turn into white silver-wire vessels. Stage of peripheral ... Salmon patches occur due to retinal hemorrhages, especially in mid-peripheral retina, adjacent to a retinal arteriole. Since ...
The arterioles end by opening freely into the splenic pulp; their walls become much attenuated, they lose their tubular ... The arterioles, supported by the minute trabeculae, traverse the pulp in all directions in bundles (penicilli) of straight ... The altered coat of the arterioles, consisting of adenoid tissue, presents here and there thickenings of a spheroidal shape, ... or central arterioles). Branches of the central arteries are given to the red pulp, and these are called penicillar arteries). ...
However, this assumption fails when considering forward flow within arterioles. At the microscopic scale, the effects of ...
... s are substances or medications that preferentially dilate arterioles. When used on people with certain ...
The germinal centers are supplied by arterioles called penicilliary radicles. Until the fifth month of prenatal development, ...
The rest passes into an efferent arteriole. The diameter of the efferent arteriole is smaller than that of the afferent, and ... The arterioles from the renal circulation enter and leave the glomerulus at the vascular pole. The glomerular filtrate leaves ... Although the figure labels the efferent vessel as a vein, it is actually an arteriole.) Glomerulus is red; Bowman's capsule is ... Each glomerulus receives its blood supply from an afferent arteriole of the renal circulation. The glomerular blood pressure ...
"Renal Vasculature: Efferent Arterioles & Peritubular Capillaries". *Histology image: 15901lba - Histology Learning System at ...
The arterioles are thickened and occlusion by thrombi are occasionally present. Though a neuroma is a soft-tissue abnormality ...
Words related to arterioles:. = 48 && event.charCode <= 57 value="Num letters..." onfocus="inputFocus(this)" onblur="inputBlur ...
... hands caused by spasms in arterioles (small arteries) of the skin. Less commonly, the feet are affected. The fingers or toes ... of the smallest arteries, or arterioles, is reached. The threadlike arterioles carry blood to networks of microscopic vessels ... In arterioles, the tunica intima is still present as a lining covered by a layer of thin longitudinal fibres; however,… ... The transition from artery to arteriole is a gradual one, marked by a progressive thinning of the vessel wall and a decrease in ...
... Arterioles are the smallests vessels of the arterial system, with a diameter of about 1/3 millimeter or ... OTHER ARTERIOLES: Most of the arterioles in the body are affected to at least some extent by local chemical factors that adjust ... This is determined by the lumped effects of all the arterioles in the body and is termed the total peripheral resistance. ... The arterioles are absolutely a key effector organ in the control of mean arterial pressure. Recall our model for the arterial ...
Pulmonary arterioles are a noteworthy exception as they vasodilate in response to high oxygen. Brain arterioles are ... An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to ... Arterioles have muscular walls (usually only one to two layers of smooth muscle) and are the primary site of vascular ... Arterioles receive autonomic nervous system innervation and respond to various circulating hormones in order to regulate their ...
Arteries and arterioles: …off short branches called the afferent arterioles, which carry blood to the glomeruli where they ... Other articles where Afferent arteriole is discussed: renal system: ... In renal system: Arteries and arterioles. …off short branches called the afferent arterioles, which carry blood to the ... of plasma so that the afferent arterioles skim off more plasma than cells. If the arteriolar blood pressure rises, the skimming ...
The efferent arterioles are blood vessels that are part of the urinary tract of organisms. Efferent (from Latin ex + ferre) ... The efferent arterioles form a convergence of the capillaries of the glomerulus, and carry blood away from the glomerulus that ... The efferent arterioles of the juxtamedullary glomeruli are much different. They do break up, but they form bundles of vessels ... The efferent arterioles of the undifferentiated cortical glomeruli are the most complex. Promptly on leaving the glomerulus ...
Afferent arterioles synonyms, Afferent arterioles pronunciation, Afferent arterioles translation, English dictionary definition ... of Afferent arterioles. adj. Carrying inward to a central organ or section, as nerves that conduct impulses from the periphery ... redirected from Afferent arterioles). Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia. af·fer·ent. (ăf′ər-ənt). adj. ... But one key way hypertension hurts kidneys is by blunting the function of afferent arterioles, tiny blood vessels that feed the ...
Definition of capillary arteriole. Provided by Stedmans medical dictionary and Drugs.com. Includes medical terms and ...
Efferent Arteriole. The efferent arteriole carries blood away from the glomerulus. Because it has a smaller diameter than the ... afferent arteriole, it creates some resistance to blood flow, producing the back-up of blood in the glomerulus which creates ...
... very tiny branches coming off of my small artery and lets follow this one right here and this one is my arterial arteriole so ... even smaller artery lets call it small artery small artery from there were actually going to get into what we call arterioles ... here and actually a lot of that resistance and change in the constriction or vasoconstriction is happening at the arteriole ...
precapillary arteriole synonyms, precapillary arteriole pronunciation, precapillary arteriole translation, English dictionary ... definition of precapillary arteriole. n. One of the small terminal branches of an artery, especially one that connects with a ... arteriole. (redirected from precapillary arteriole). Also found in: Thesaurus, Medical, Encyclopedia.. Related to precapillary ... arteriole. (ɑːˈtɪərɪˌəʊl) n. (Anatomy) anatomy any of the small subdivisions of an artery that form thin-walled vessels ending ...
Afferent arterioles were perfused at 60 mm Hg to provide some basal tone and incubated with graded concentration of H2O2 for 15 ... TP receptor-mediated vasoconstriction in microperfused afferent arterioles: role O2- and NO. Am J Physiol. 2000;48:F302-F308. ... Superoxide Modulates Myogenic Contractions of Mouse Afferent Arterioles. En Yin Lai, Anton Wellstein, William J. Welch, ... Angiotensin II, reactive oxygen species, and Ca2+ signaling in afferent arterioles. Am J Physiol Renal Physiol. 2005;289:F1012- ...
G. L. Baumbach, C. D. Sigmund, T. Bottiglieri, and S. R. Lentz, "Structure of cerebral arterioles in cystathionine β-synthase- ... G. L. Baumbach, C. D. Sigmund, and F. M. Faraci, "Structure of cerebral arterioles in mice deficient in expression of the gene ... G. L. Baumbach, S. P. Didion, and F. M. Faraci, "Hypertrophy of cerebral arterioles in mice deficient in expression of the gene ... G. L. Baumbach, P. B. Dobrin, M. N. Hart, and D. D. Heistad, "Mechanics of cerebral arterioles in hypertensive rats," ...
Treatment of visceral arterioles with L-NAME (light gray, triangle symbol) completely abolished indomethacin-induced ... Arterioles from visceral fat exhibited impaired endothelium-dependent, acetylcholine-mediated vasodilation, compared to the ... Cyclooxygenase inhibition improves endothelial vasomotor dysfunction of visceral adipose arterioles in human obesity.. Farb MG1 ... Vasomotor function was assessed in response to endothelium-dependent agonists using videomicroscopy of small arterioles from ...
Synonyms for arteriole at Thesaurus.com with free online thesaurus, antonyms, and definitions. Find descriptive alternatives ... RELATED WORDS AND SYNONYMS FOR ARTERIOLE. blood vessel. nounblood flow pathway ...
... changes in neural activity to alterations in cerebral blood flow by eliciting vasoconstriction or vasodilation of arterioles. ... Brain metabolism dictates the polarity of astrocyte control over arterioles Nature. 2008 Dec 11;456(7223):745-9. doi: 10.1038/ ... changes in neural activity to alterations in cerebral blood flow by eliciting vasoconstriction or vasodilation of arterioles. ...
... Microvasc Res. 2008 Nov;76(3):217-23. doi: ... Notably, the constriction occurred only in the arterioles that were in closer proximity to the venules draining the retina. ... Acute administration of ozagrel reversed the constriction of the closely venule-paired arterioles. In summary, the results ...
Effect of intermittent normoxia on muscularization of pulmonary arterioles induced by chronic hypoxia in rats.. Kay JM, Suyama ... We studied the effect of continuous and intermittent normoxia for 6 and 20 wk on the muscularization of pulmonary arterioles in ...
Arterioles of the Lenticular Nucleus in CADASIL. Qing Miao, Timo Paloneva, Seppo Tuisku, Susanna Roine, Minna Poyhonen, Matti ... Arterioles of the Lenticular Nucleus in CADASIL. Qing Miao, Timo Paloneva, Seppo Tuisku, Susanna Roine, Minna Poyhonen, Matti ... Arterioles of the Lenticular Nucleus in CADASIL. Qing Miao, Timo Paloneva, Seppo Tuisku, Susanna Roine, Minna Poyhonen, Matti ...
1. Measurements of the internal diameters and lengths of branchless segments of mesenteric arterioles of frogs and mice show ... Saunders and Knisely (63) found that the maximal internal diameters to which the terminal mesenteric arterioles can distend as ... Saunders and Knisely (63) found unagglutinated blood flowing at physiologic rates through terminal arterioles as narrow as, ...
This manuscript describes a simple and reproducible protocol for isolation of intracerebral arterioles (a group of blood ... a group of blood vessels encompassing parenchymal arterioles, penetrating arterioles and pre-capillary arterioles) from mice, ... This manuscript describes a simple and reproducible protocol for isolation of intracerebral arterioles ( ...
Cadmium Toxicity on Arterioles Vascular Smooth Muscle Cells of Spontaneously Hypertensive Rats. Benny Washington 1,* , Shunta ... "Cadmium Toxicity on Arterioles Vascular Smooth Muscle Cells of Spontaneously Hypertensive Rats." Int. J. Environ. Res. Public ... Cadmium Toxicity on Arterioles Vascular Smooth Muscle Cells of Spontaneously Hypertensive Rats. International Journal of ... Washington, B.; Williams, S.; Armstrong, P.; Mtshali, C.; Robinson, J.T.; Myles, E.L. Cadmium Toxicity on Arterioles Vascular ...
Parenchymal arterioles (PAs) are high-resistance vessels in the brain that connect pial vessels to the microcirculation. We ... BACKGROUND AND PURPOSE: Parenchymal arterioles (PAs) are high-resistance vessels in the brain that connect pial vessels to the ... Sensitivity of the contractile apparatus to calcium was measured in permeabilized arterioles using Staphylococcus aureus α- ...
reported that, in the retinal arterioles, UI caused vasodilation only in endothelin-1 (ET-1)-pre-contracted arterioles but did ... Previous studies have reported the involvement of various K channels in the vasodilation of the retinal arterioles [9,10,12,18, ... Dilation of retinal arterioles induced by UI. The basal tone in all vessels (n=38) ranged from 53% to 78% (average, ~59% ± 4%) ... Cannulated, pressurized arterioles were bathed in physiologic salt solution (PSS) with albumin (0.1%) at 36 to 37 °C to allow ...
Coloured transmission electron micrograph (TEM) of a section through the wall of an arteriole, showing smooth muscle (brown), ... Caption: Arteriole. Coloured transmission electron micrograph (TEM) of a section through the wall of an arteriole, showing ... Keywords: anatomical, anatomy, arteriole, basal lamina, basement lamina, basement membrane, biological, biology, blood vessel, ...
What is capillary arteriole? Meaning of capillary arteriole medical term. What does capillary arteriole mean? ... Looking for online definition of capillary arteriole in the Medical Dictionary? capillary arteriole explanation free. ... capillary arteriole. cap·il·lar·y ar·te·ri·ole. a minute artery that terminates in a capillary. ... Capillary arteriole , definition of capillary arteriole by Medical dictionary https://medical-dictionary.thefreedictionary.com/ ...
Arteriole (Science: anatomy) a minute artery, especially one that leads to a capillary. One of the small thin-walled arteries ... These arterioles get progressively smaller the more distanced they are from the heart, as most of the blood supply is required ... that end in capillaries.Arterioles are responsible for carrying oxygenated blood from the heart to all over the body. ... Retrieved from "https://www.biology-online.org/dictionary/index.php?title=Arteriole&oldid=83013" ...
Constriction of Pial Arterioles Produced by Prostaglandin F2α. WILLIAM I. ROSENBLUM ... Prostaglandin F2α constricted pial arterioles when locally applied to the cerebral surface. Norepinephrine and serotonin each ...
Functional Assessment of Isolated Coronary Arterioles. Individual left ventricular subepicardial arterioles (≈1 mm in length; ... In coronary arterioles isolated from normotensive pigs, both adenosine (Figure 1A) and serotonin (Figure 1B) produced a dose- ... Coronary arterioles (5 to 7 vessels/sample, ≈100 μm inner diameter, 1 to 2 mm in length) from normotensive and hypertensive ... Coronary arterioles from normotensive (NT) and hypertensive (HT) pigs were isolated and pressurized for in vitro study. NT ...
In contrast, vasomotion and dynamic Ca2+ signals were rarely observed in ear arterioles of anesthetized exMLCK biosensor mice. ... In contrast, vasomotion and dynamic Ca2+ signals were rarely observed in ear arterioles of anesthetized exMLCK biosensor mice. ... In a typical arteriole with an average diameter of ~35 μm, oscillatory vasomotion of a 5-6 μm magnitude was accompanied by ... In a typical arteriole with an average diameter of ~35 μm, oscillatory vasomotion of a 5-6 μm magnitude was accompanied by ...
  • The pulmonary artery distributes blood to the alveoli via intrapulmonary arteries and arterioles that follow the branching pattern of the airways. (rupress.org)
  • Mean blood pressure drops over the whole circulation, although most of the fall occurs along the small arteries and arterioles. (hyperleap.com)
  • The increased peripheral resistance in established hypertension is mainly attributable to structural narrowing of small arteries and arterioles, although a reduction in the number or density of capillaries may also contribute. (hyperleap.com)
  • Intracerebral parenchymal arterioles (PAs), which include parenchymal arterioles, penetrating arterioles and pre-capillary arterioles, are high resistance blood vessels branching out from pial arteries and arterioles and diving into the brain parenchyma. (unr.edu)
  • Arteries and arterioles are two types of blood vessels that mainly carry oxygenated blood . (pediaa.com)
  • The main difference between arteries and arterioles is that arteries are the major blood vessels that carry oxygenated blood whereas arterioles are the small branches of arteries that lead to capillaries . (pediaa.com)
  • The main function of both arteries and arterioles is to carry nutrients and oxygen to different types of tissues in the body. (pediaa.com)
  • Arteries and arterioles carry oxygenated blood. (pediaa.com)
  • Both arteries and arterioles occur together in a closed circulation system. (pediaa.com)
  • Both arteries and arterioles are elastic blood vessels, consisting of muscular walls. (pediaa.com)
  • Both arteries and arterioles consist of a lumen. (pediaa.com)
  • Both arteries and arterioles are under the control of the sympathetic nervous system. (pediaa.com)
  • Nephrosclerosis, hardening of the walls of the small arteries and arterioles (small arteries that convey blood from arteries to the even smaller capillaries) of the kidney. (kidneytreatment.site)
  • Similar to other vascular beds, retinal pressure autoregulation is thought to be mediated largely through the myogenic response of small arteries and arterioles which constrict when transmural pressure increases or dilate when it decreases. (disease-connect.org)
  • The threadlike arterioles carry blood to networks of microscopic vessels called capillaries, which supply nourishment and oxygen to the tissues and carry away carbon dioxide and other products of metabolism by way of the veins. (britannica.com)
  • An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. (wikipedia.org)
  • The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries. (wikipedia.org)
  • off short branches called the afferent arterioles, which carry blood to the glomeruli where they divide into four to eight loops of capillaries in each glomerulus. (britannica.com)
  • The efferent arterioles form a convergence of the capillaries of the glomerulus, and carry blood away from the glomerulus that has already been filtered. (wikipedia.org)
  • One of the small thin-walled arteries that end in capillaries.Arterioles are responsible for carrying oxygenated blood from the heart to all over the body . (biology-online.org)
  • The renal afferent and efferent arterioles regulate glomerular inflow and outflow resistances, thereby controlling the pressure within the intervening glomerular capillaries (PGC). (ahajournals.org)
  • We studied the localization of blood flow control in skeletal muscle by short-term microocclusions (30-60 seconds) of capillaries and arterioles of the pectoralis muscle in anesthetized frogs ( Rana pipiens ). (ahajournals.org)
  • Arteries branch into arterioles within organs and deliver blood to the capillaries. (gettyimages.it)
  • A metarteriole is a short microvessel in the microcirculation that links arterioles and capillaries. (hyperleap.com)
  • Arterioles are narrower arteries that branch off from the ends of arteries and carry blood to capillaries. (innerbody.com)
  • These arteries further branch into arterioles and capillaries at tissues . (pediaa.com)
  • Arterioles are the small branches of arteries that lead to capillaries. (pediaa.com)
  • Here we show that Notch signalling in endothelial cells leads to the expansion of haematopoietic stem cell niches in bone, which involves increases in CD31-positive capillaries and platelet-derived growth factor receptor-β (PDGFRβ)-positive perivascular cells, arteriole formation and elevated levels of cellular stem cell factor. (nature.com)
  • This anatomical arrangement ideally positions capillaries to detect neuronal activity and communicate it to upstream arterioles. (pnas.org)
  • 1) Diabetic retinopathy is a microangiopathy affecting precapillary arterioles and post-capillary venules. (thefreedictionary.com)
  • Notably, the constriction occurred only in the arterioles that were in closer proximity to the venules draining the retina. (nih.gov)
  • They discovered that people with FM had more vasodilation in the tiny little arterioles (smaller than arteries) that connect to the tiny little venules (smaller than veins) that connect to each other through shunts. (prohealth.com)
  • Yet these tiny arterioles and venules deliver oxygen and nutrients to energy-hungry brain cells and carry away wastes. (thefreedictionary.com)
  • Differences in the capsaicin-induced dilation of arterioles and venules in rat striated muscle. (aspetjournals.org)
  • Experiments were done to determine 1) whether capsaicin has similar effects on larger arterioles and venules and 2) whether relaxation involves endogenous CGRP and synthesis of endothelium-derived relaxing factor. (aspetjournals.org)
  • N-nitro-L-arginine methyl ester also blocked CGRP-induced dilation of both orders of venules, but not arterioles. (aspetjournals.org)
  • These data suggest that capsaicin-induced dilation may involve synthesis of endothelium-derived relaxing factor in the venules but not in the arterioles. (aspetjournals.org)
  • A velocity profile equation for blood flow in small arterioles and venules of small mammals in vivo and an evaluation based on literature data. (biomedsearch.com)
  • An empirical parametric equation with 2 bluntness parameters was introduced for describing the velocity profile of blood in the small arterioles and venules of small mammals, in vivo, with the basic approximations of the axisymmetric flow in cylindrical geometry, zero velocity at the wall and a blunter than parabolic flow profile. (biomedsearch.com)
  • Leukocyte-endothelial interactions in pial arterioles and venules on development of cerebral ischemia in rats. (curehunter.com)
  • Specimens were obtained from 40 arterioles and 30 venules (diameter up to 40 micron) of the pia mater from Wistar rats (n = 7) subjected to ischemia for 5 h to respiratory arrest. (curehunter.com)
  • They are the smallest blood vessels in the body: they convey blood between the arterioles and venules. (hyperleap.com)
  • The middle layer is poorly developed so that venules have thinner walls than arterioles. (hyperleap.com)
  • One mechanism that can lower blood pressure is the direct dilation of arterioles by docosahexaenoic metabolites. (elsevier.com)
  • The constriction and the dilation of arterioles are controlled by the sympathetic nervous system . (pediaa.com)
  • The constriction of arterioles causes the blood pressure to increase while dilation of arterioles causes the blood pressure to decrease. (pediaa.com)
  • Any reduction in the availability of NO due to increased levels of superoxide released by high pressure in the arterioles (or in response to other pathophysiological alterations in hypertension) would likely cause an impaired dilation of arterioles in response to shear stress- and other NO-dependent vasodilator stimuli, leading to the maintained elevation of wall shear stress and peripheral vascular resistance that exists in hypertension. (alpfmedical.info)
  • First, let's make a list of the most important factors causing vasoconstriction or vasodilation in arterioles. (washington.edu)
  • Sympathetic nerves control the skin arterioles for this purpose, with greater release of norepinephrine causing vasoconstriction . (washington.edu)
  • Other mechanisms of Amphotericin B induced nephrotoxicity suggested in the literature are direct toxic effects to the afferent arterioles and tubules and direct renal and systemic vasoconstriction. (thefreedictionary.com)
  • Calcium signalling in astrocytes couples changes in neural activity to alterations in cerebral blood flow by eliciting vasoconstriction or vasodilation of arterioles. (nih.gov)
  • Postischemic Reperfusion Causes Smooth Muscle Calcium Sensitization and Vasoconstriction of Parenchymal Arterioles. (biomedsearch.com)
  • Vasoconstriction must be balanced with vasodilation, particularly in the arterioles that supply tissues with blood. (sciencemag.org)
  • 9 10 Moreover, we have shown that Ang II-induced afferent vasoconstriction is closely coupled to membrane depolarization, whereas the contractile response of the efferent arteriole to Ang II is fully dissociated from changes in membrane potential. (ahajournals.org)
  • Gonadectomy potentiated the responsiveness of the afferent arteriole to ET B -induced vasoconstriction in females, but not males, suggesting that female sex hormones influence ET B -mediated vasoconstriction in the renal microcirculation. (springer.com)
  • Effects of endothelin receptor antagonist on cyclosporine-induced vasoconstriction in isolated rat renal arterioles. (semanticscholar.org)
  • Dilatation of cerebral arterioles in response to nitroglycerin and vasoconstriction in response to the thromboxane analogue (U-46619) were similar in non-ethanol- fed and ethanol-fed rats. (elsevier.com)
  • The efferent arterioles are blood vessels that are part of the urinary tract of organisms. (wikipedia.org)
  • The efferent arterioles of the undifferentiated cortical glomeruli are the most complex. (wikipedia.org)
  • The efferent arterioles of the juxtamedullary glomeruli are much different. (wikipedia.org)
  • To compensate, the efferent arterioles constrict to a greater degree than the other arteries, in response to increased levels of angiotensin II. (wikipedia.org)
  • 27) has measured renal arteriolar diameter using a vascular cast technique and have found that the afferent arterioles were constricted while the efferent arterioles were dilated in DOCA-salt hypertensive rats. (thefreedictionary.com)
  • The effects of atriopeptin III (AP III) on in vitro prepared afferent (AA) and efferent arterioles (EA) from rat kidneys were tested in a system in which lumen diameter could be measured. (physiology.org)
  • Nifedipine blocked the Ang II-induced Ca 2+ influx in afferent arterioles but not in efferent arterioles. (ahajournals.org)
  • SKF 96365 inhibited Ang II-induced Ca 2+ entry in efferent arterioles and CPA-induced Ca 2+ entry in efferent myocytes over identical concentrations. (ahajournals.org)
  • 2 The relative reactivity of the afferent versus efferent arterioles to vasoconstrictors is also modified by physiological or pathophysiological conditions. (ahajournals.org)
  • The possible role of store-operated Ca 2+ influx was investigated using myocytes freshly dispersed from individually isolated afferent and efferent arterioles. (ahajournals.org)
  • Nitric oxide synthase inhibition activates L- and T-type Ca2+ channels in afferent and efferent arterioles. (semanticscholar.org)
  • Because arginase has recently been shown to modulate NO-mediated dilation of coronary arterioles by reducing l -arginine availability, we hypothesized that upregulation of vascular arginase in hypertension contributes to decreased NO-mediated vasodilation. (ahajournals.org)
  • Coronary arterioles from normotensive (NT) and hypertensive (HT) pigs were isolated and pressurized for in vitro study. (ahajournals.org)
  • These results suggest that NO-mediated dilation of coronary arterioles is inhibited in hypertension by an increase in arginase activity in EC, which limits l -arginine availability to NOS for NO production. (ahajournals.org)
  • We have recently documented the constitutive expression of arginase-I in porcine coronary arterioles and demonstrated its functional role in modulating coronary microvascular tone under physiological 12 and pathophysiological conditions. (ahajournals.org)
  • Flow-mediated dilation (FMD) of coronary arterioles was investigated in DM ( n = 41) and non-DM ( n = 37) patients undergoing heart surgery. (diabetesjournals.org)
  • Previously, we demonstrated that in a mouse model of type 2 DM ( db / db mice), WSS-induced dilation is diminished in coronary arterioles, which is due to the reduced availability of nitric oxide (NO) ( 10 , 11 ). (diabetesjournals.org)
  • Vascular endothelium contains cytochrome P-450 epoxygenases that transform the n-6 fatty acid arachidonate into epoxyeicosatrienoic acids (EETs), potent dilators of coronary arterioles and activators of large-conductance calcium-activated potassium (BK Ca ) channels. (elsevier.com)
  • n = 5) BK Ca channels in myocytes from the porcine coronary arterioles. (elsevier.com)
  • The transition from artery to arteriole is a gradual one, marked by a progressive thinning of the vessel wall and a decrease in the size of the lumen, or passageway. (britannica.com)
  • The vessel is an arteriole, a small artery. (fineartamerica.com)
  • Layers in an artery and arteriole. (brainscape.com)
  • While these studies provided valuable information, it is difficult to know how well the responses of SMCs of the pulmonary artery reflect the physiology of small intrapulmonary arterioles. (rupress.org)
  • Arterioles are the smallest type of artery. (medicalnewstoday.com)
  • We demonstrate that this conjugated nanoparticle binds to CVA deposits in arterioles of AD transgenic mice (Tg2576) after infusion into the external carotid artery using 3 different approaches. (elsevier.com)
  • However, the arterioles of skeletal muscle, cardiac muscle, and pulmonary circulation vasodilate in response to these hormones when they act on beta-adrenergic receptors. (wikipedia.org)
  • In skeletal muscle arterioles, this feedback can be activated by Ca 2+ signals passing from smooth muscle through gap junctions to endothelial cells, which protrude through holes in the internal elastic lamina to make contact with vascular smooth muscle cells. (sciencemag.org)
  • Skeletal muscle arterioles dilate in response to application of acetylcholine (ACh), eliciting a conducted vasodilation (CVD) that travels along unbranched segments without decrement. (umsystem.edu)
  • On the basis of studies of endothelial cells in culture, suggesting that platelet endothelial cell adhesion molecule-1 (PECAM-1) is specifically involved in sensing and coupling high temporal gradients of fluid shear stress with activation of eNOS, we hypothesized that dilations of isolated skeletal muscle arterioles from PECAM-1 knockout mice (PECAM-KO) will be reduced to rapid increases in WSS elicited by increases in perfusate flow. (ahajournals.org)
  • Nitric oxide-dependent relaxation and prostaglandin-mediated vasodilation are both impaired in skeletal muscle arterioles of spontaneously hypertensive rats. (alpfmedical.info)
  • Arterioles are the smallests vessels of the arterial system, with a diameter of about 1/3 millimeter or smaller. (washington.edu)
  • An increase in the media to lumenal diameter ratio has been observed in hypertensive arterioles (arteriolosclerosis) as the vascular wall thickens and/or lumenal diameter decreases. (wikipedia.org)
  • Arterioles receive autonomic nervous system innervation and respond to various circulating hormones in order to regulate their diameter. (wikipedia.org)
  • Because it has a smaller diameter than the afferent arteriole, it creates some resistance to blood flow, producing the back-up of blood in the glomerulus which creates higher pressure in the glomerular cavity. (innerbody.com)
  • Saunders and Knisely (63) found unagglutinated blood flowing at physiologic rates through terminal arterioles as narrow as, depending upon species, from 5 to 7.7 micra in diameter. (ebscohost.com)
  • In a typical arteriole with an average diameter of ~35 μm, oscillatory vasomotion of a 5-6 μm magnitude was accompanied by nearly uniform [Ca 2+ ] oscillations from ~0.1 to 0.5 μM, with maximum [Ca 2+ ] occurring immediately before the rapid decrease in diameter. (frontiersin.org)
  • Porcine retinal arterioles (60-90 µm in internal diameter) were isolated, cannulated and pressurized (55 cmH 2 O) without flow for in vitro study. (arvojournals.org)
  • 10 −6 to 5×10 −5 mol/L) were studied in cannulated and pressurized gracilis muscle arterioles (≈75 μm in diameter) isolated from 12-week-old male SHR before and after incubation with 10 −9 mol/L 17β-estradiol (17β-E 2 ) for 16 to 18 hours. (ahajournals.org)
  • After incubation with 17β-E 2 , basal diameter of arterioles was significantly increased (by ≈10%), and flow-induced dilation was significantly enhanced (79.8±2.9 versus 103.7±3.7 μm at 25 μL/min), resulting in a lowered shear stress (62.0±9.1 versus 32.5±4.2 dyne/cm 2 ). (ahajournals.org)
  • Gonadectomy had no significant effect on control arteriole diameter. (springer.com)
  • Selective ET B receptor activation by S6c induced a concentration-dependent decline in afferent arteriole diameter, with 10 −8 M S6c decreasing diameter by 77 ± 3 and 76 ± 3% in sham male and female rats, respectively. (springer.com)
  • To study the effect of an acute increase in the arterial blood pressure on the diameter response of retinal arterioles supplying areas with focal diabetic macular oedema before and after laser photocoagulation, and control arterioles supplying areas without oedema. (bmj.com)
  • In 17 diabetic patients the diameter response of arterioles after an increase in the arterial blood pressure induced by isometric exercise was studied using the retinal vessel analyser (RVA). (bmj.com)
  • In each patient a study arteriole supplying a focal area of macular oedema as well as a control arteriole supplying a retinal area without retinopathy lesions was selected, and the diameter response of these vessels was performed immediately before, and 1 hour and 3 months after focal laser photocoagulation of the focal oedema area. (bmj.com)
  • The diameter response was impaired in both study arterioles and control arterioles before focal laser photocoagulation. (bmj.com)
  • The treatment induced regression of the focal retinal oedema, but did not affect the diameter response in the arteriole supplying this area (p = 0.85). (bmj.com)
  • Impairment of the diameter response in small arterioles from diabetic patients does not parallel the regional distribution of retinopathy lesions. (bmj.com)
  • What are the local and reflex mechanisms for the control of arteriole diameter. (brainscape.com)
  • The arteriolar myogenic response, described as the ability of arterioles to regulate their diameter to changes in intra-luminal pressure, is prominent in the control of vascular resistance, autoregulation of blood flow and control of capillary hydrostatic pressure. (umsystem.edu)
  • The overall aim of the studies described in this dissertation was to investigate the relationships amongst intraluminal pressure, arteriolar myogenic tone, and transient intracellular Ca2+ regulation with particular emphasis on the mechanisms underlying the generation and propagation of Ca2+ waves.First order arterioles (passive diameter 100 - 200 μm) were dissected from the cremaster muscle tissue of male Sprague Dawley rats. (umsystem.edu)
  • Using intravital microscopy, we measured diameter of cerebral arterioles in non-ethanol- and ethanol-fed rats in response to acetylcholine, histamine, ADP, the thromboxane analogue (U- 46619), and nitroglycerin. (elsevier.com)
  • 7 Recently, ROS have been implicated in the enhanced myogenic contractions of renal afferent arterioles from spontaneously hypertensive rats (SHRs), 8 although the more modest myogenic contractions of normotensive rats were independent of ROS. (ahajournals.org)
  • Background -Endothelial nitric oxide (NO)-mediated responses are impaired in arterioles of male spontaneously hypertensive rats (SHR), but they are still present in female SHR. (ahajournals.org)
  • Agonists such as norepineph-rine and acetylcholine also cause an increased release of the endothelium-dependent vasoconstrictors thromboxane A2 and/or PGH2 in arterioles and resistance arteries of hypertensive rats, leading to a reduced sensitivity to acetylcholine and to an enhanced vasoconstrictor response to norepinephrine. (alpfmedical.info)
  • As noted earlier, arteriolar dilation in response to the physiological stimulus of increased flow or shear stress is also impaired in arterioles of hypertensive rats. (alpfmedical.info)
  • The impaired relaxation of arterioles of spontaneously hypertensive rats in response to increased flow and shear stress appears to be due to an impairment of the NO-mediated portion of flow-dependent dilation, but may also involve an enhanced release of endothelium-derived vasoconstrictor factors such as PGH2. (alpfmedical.info)
  • Fluorescence deconvolution micrograph of a section through kidney tissue, showing an arteriole (upper right to lower left), a small arterial blood vessel. (sciencephoto.com)
  • For example, angiotensin II (Ang II), which is capable of constricting both vessels, 3 preferentially constricts the efferent arteriole in the setting of renal arterial stenosis, thereby maintaining PGC and GFR in the face of reduced perfusion pressure. (ahajournals.org)
  • The elastic tissue adds structural integrity to arterial and larger arteriolar walls during pulsatile distension from higher intravascular pressure, and the retained muscular layer in small arterioles helps provide an important component of the pre-capillary sphincter mechanism, whereby regulation of blood flow to capillary beds occurs. (arkanalabs.com)
  • Atherosclerosis , as well as, arterial stenosis may affect the blood flow through the arteriole. (pediaa.com)
  • We studied the effect of continuous and intermittent normoxia for 6 and 20 wk on the muscularization of pulmonary arterioles in rats with chronic hypoxic hypertension. (nih.gov)
  • 4] causes inflammation resulting in arteriole occlusion and hypertension," said Joanne Quan, MD, Chief Medical Officer at Eiger. (thefreedictionary.com)
  • It has been proposed that the elevated hemodynamic forces present in hypertension may initiate alterations of signaling pathways in the endothelium and smooth muscle cells of arterioles that could, in turn, enhance the release of reactive oxygen species such as superoxide. (alpfmedical.info)
  • Effect of intermittent normoxia on muscularization of pulmonary arterioles induced by chronic hypoxia in rats. (nih.gov)
  • Control afferent arteriole diameters at 100 mmHg were similar between sham male and female rats averaging 14.6 ± 0.3 and 15.3 ± 0.3 μm, respectively. (springer.com)
  • In non-ethanol-fed rats, acetylcholine, histamine, and ADP produced dose-related dilatation of cerebral arterioles. (elsevier.com)
  • Although ET-1, the predominant endogenous isoform of ET, has been shown to cause constriction of retinal vessels, the expression and functional significance of its synthesis and the involved specific ET receptors in retinal arterioles remain unknown. (arvojournals.org)
  • The authors examined the roles of ET A and ET B receptors and of endothelin-converting enzyme (ECE)-1 in ET-1-induced vasomotor responses of single retinal arterioles. (arvojournals.org)
  • ET-1 elicits constriction of retinal arterioles predominantly through the activation of smooth muscle ET A receptors. (arvojournals.org)
  • Sympathetic nerve stimulation causes a constriction of submucosal arterioles that is mediated by ATP acting at P2 receptors. (aspetjournals.org)
  • These data indicate that P2X receptors mediate constriction of submucosal arterioles. (aspetjournals.org)
  • RePub, Erasmus University Repository: Facilitated diffusion of angiotensin II from perivascular interstitium to AT1 receptors of the arteriole. (eur.nl)
  • Background: A kinetic model for the binding of angiotensin (Ang) II to AT1 receptors (AT1R) in arterioles in vivo did suggest a novel mechanism of stimulus amplification. (eur.nl)
  • These results indicate that 5-HT, acting via 5-HT 2 receptors, induces arteriole contraction by initiating Ca 2+ oscillations and that KCl induces contraction via Ca 2+ transients resulting from the overfilling of internal Ca 2+ stores. (rupress.org)
  • Activation of GLP-1 receptors on vascular smooth muscle cells reduces the autoregulatory response in afferent arterioles and increases renal blood flow. (semanticscholar.org)
  • We further show that PIP 2 depletion through activation of G q protein-coupled receptors (G q PCRs) cripples capillary-to-arteriole signal transduction in vitro and in vivo, highlighting the potential regulatory linkage between G q PCR-dependent and electrical neurovascular-coupling mechanisms. (pnas.org)
  • The process of hyalinosis invariably also affects the glomerular arteriole in moderately advanced diabetic nephropathy. (thefreedictionary.com)
  • This manuscript describes a simple and reproducible protocol for isolation of intracerebral arterioles (a group of blood vessels encompassing parenchymal arterioles, penetrating arterioles and pre-capillary arterioles) from mice, to be used in pressure myography, immunofluorescence, biochemistry, and molecular studies. (jove.com)
  • BACKGROUND AND PURPOSE: Parenchymal arterioles (PAs) are high-resistance vessels in the brain that connect pial vessels to the microcirculation. (biomedsearch.com)
  • We previously found that capsaicin can dilate third-order arterioles in striated muscle by a mechanism that appears to involve release of endogenous calcitonin gene-related peptide (CGRP). (aspetjournals.org)
  • They found a reduced ability to dilate of the brain arterioles in patients with MS in respect to control participants. (jamanetwork.com)
  • Thus, rat kidneys with oxidative stress caused by transforming growth factor-β 9 or by a high salt intake and angiotensin II infusion 10 had impaired myogenic responses that were preserved by the redox-cycling nitroxide Tempol, 11 whereas exposure of cerebral arterioles to ROS abolished autoregulation. (ahajournals.org)
  • Prostaglandin F 2α constricted pial arterioles when locally applied to the cerebral surface. (ahajournals.org)
  • These arterioles are a central player in the regulation of cerebral blood flow both globally (cerebrovascular autoregulation) and locally (functional hyperemia). (unr.edu)
  • The purpose of this study was to examine the effects of ethanol exposure on responses of cerebral arterioles in vivo. (elsevier.com)
  • Thus these findings suggest that chronic ethanol exposure impairs responses of cerebral arterioles to agonists, which produce dilatation via the release of an endothelium-derived relaxing factor. (elsevier.com)
  • Mayhan, W 1992, ' Responses of cerebral arterioles during chronic ethanol exposure ', American Journal of Physiology - Heart and Circulatory Physiology , vol. 262, no. 3 31-3. (elsevier.com)
  • Our data suggests that from young to middle-age, a well-regulated capillary oxygen supply maintains the oxygen availability in cerebral tissue, despite decreased tissue pO 2 next to arterioles. (nature.com)
  • Notable in this context, we recently reported that increases in extracellular K + concentration ([K + ] o ), such as those evoked by neuronal activity, trigger an ascending hyperpolarizing signal that dilates upstream arterioles and enhances capillary red blood cell (RBC) flux and cerebral blood flow ( 3 ). (pnas.org)
  • Porcine retinal arterioles were isolated, cannulated, and pressurized without flow in vitro. (molvis.org)
  • To exclude systemic confounding effects, porcine retinal arterioles were isolated for vasoreactivity and molecular studies. (arvojournals.org)
  • Arterioles were cannulated, pressurized and superperfused with a modified Krebs buffer solution at 34oC and allowed to develop spontaneous myogenic tone. (umsystem.edu)
  • Here, we review and extend previous work on the expression and spatial distribution of the plasma membrane and sarcoplasmic reticulum ion channels present in retinal vascular smooth muscle cells (VSMCs) and discuss their contribution to pressure-induced myogenic tone in retinal arterioles. (disease-connect.org)
  • Furthermore, 7-NI treatment abolished the glutamate-induced dilatation of pial arterioles. (elsevier.com)
  • We conclude that NO may be involved in aprikalim-induced dilation of pial arterioles. (elsevier.com)
  • A number of hormones influence arteriole tone such as angiotensin II (vasoconstrictive), endothelin (vasoconstrictive), bradykinin (vasodilation), atrial natriuretic peptide (vasodilation), and prostacyclin (vasodilation). (wikipedia.org)
  • Afferent arteriole responsiveness to endothelin receptor activation: does sex matter? (springer.com)
  • Attenuated vasoconstrictor responses to endothelin in afferent arterioles during a high-salt diet. (semanticscholar.org)
  • Myogenic mechanisms in the afferent arteriole are incompletely understood. (ahajournals.org)
  • The present study was undertaken to determine whether Ang II activates distinct Ca 2+ entry mechanisms in the afferent and efferent arteriole. (ahajournals.org)
  • FRET-based biosensor mice and two-photon imaging provided the first measurements of [Ca 2+ ] in vascular smooth muscle cells in arterioles of conscious animals. (frontiersin.org)
  • Endothelial cells protrude through holes in the internal elastic lamina in arterioles to make contact with vascular smooth muscle cells. (sciencemag.org)
  • METHODS AND Results: The model was refined in order to account for geometric characteristics of the vascular smooth muscle (VSM) cells in arterioles with a single VSM cell layer. (eur.nl)
  • constriction of small arteries (arterioles), which causes an increase in blood pressure. (britannica.com)
  • The muscular contraction of arterioles is targeted by drugs that lower blood pressure (antihypertensives), for example the dihydropyridines (nifedipine and nicardipine), which block the calcium conductance in the muscular layer of the arterioles, causing relaxation. (wikipedia.org)
  • The efferent arteriole carries blood away from the glomerulus. (innerbody.com)
  • These arterioles get progressively smaller the more distanced they are from the heart , as most of the blood supply is required by the major organs positioned close to the heart and is provided by the [[arteries. (biology-online.org)
  • The specialized blood vessels known as arterioles may be small in stature, but they play a big role in heart health. (verywellhealth.com)
  • As the most highly regulated blood vessels in the body, arterioles also have the distinction of contributing the most to the rise and fall of blood pressure. (verywellhealth.com)
  • Before this, the blood must pass through the arterioles where its speed is constantly being adjusted. (verywellhealth.com)
  • The function of the arterioles, therefore, is to regulate blood pressure so that it remains steady and less prone to fluctuation. (verywellhealth.com)
  • When the body is functioning as it should, the arterioles help ensure that the blood pressure remains within normal, healthy limits. (verywellhealth.com)
  • The arterioles regulate the amount of blood that enters these capillary networks. (thefreedictionary.com)
  • A salmon patch haemorrhage is observed in sickle cell disease and appears as an oval-shaped area of intra-retinal or pre-retinal blood, believed to occur secondary to an obstructed retinal arteriole , which subsequently ruptures. (thefreedictionary.com)
  • There are no comments for Coloured Tem Of Red Blood Cells In An Arteriole . (fineartamerica.com)
  • What changes occur to blood flow from arteries to arterioles? (brainscape.com)
  • Conclusion : Relative high MI (0.3-0.4) provides the perfusion images at arteriole level in which blood flow speed might be high. (nii.ac.jp)
  • Arterioles carry blood away from the heart. (zfin.org)
  • Blood returns to the heart via larger veins that follow a route distinct from that of arterioles and airways. (rupress.org)
  • Red and white blood cells within an arteriole. (gettyimages.it)
  • Acute hemolysis triggered the development of αIIbβ3-dependent platelet-rich thrombi in precapillary pulmonary arterioles, which led to the transient impairment of pulmonary blood flow. (jci.org)
  • Consistent with a mechanism involving ADP release from hemolyzing erythrocytes, the inhibition of platelet-P2Y12 purinergic-receptor signaling attenuated pulmonary thrombosis and rescued blood flow in the pulmonary arterioles of mice following intravascular hemolysis. (jci.org)
  • Our preliminary study suggests that the helicine arterioles are functionally inactive during penile flaccidity while they are activated during penile tumescence and continue to supply blood to the corpora also during maximum penile rigidity. (ovid.com)
  • Arterioles have the greatest collective influence on both local blood flow and on overall blood pressure. (hyperleap.com)
  • By their constriction and dilation, under the regulation of the sympathetic nervous system, arterioles are the principal controllers of blood flow and pressure. (oup.com)
  • Arterioles, like arteries, are able to use smooth muscle to control their aperture and regulate blood flow and blood pressure. (innerbody.com)
  • Like arteries, arterioles are strong and elastic blood vessels, which are composed of smooth muscle layers. (pediaa.com)
  • Arterioles are the most highly-regulated blood vessels in a circulation system. (pediaa.com)
  • Therefore, arterioles are the major regulators of blood flow and blood pressure. (pediaa.com)
  • Cyclooxygenase inhibition improves endothelial vasomotor dysfunction of visceral adipose arterioles in human obesity. (nih.gov)
  • Vasomotor function was assessed in response to endothelium-dependent agonists using videomicroscopy of small arterioles from fat. (nih.gov)
  • In the current study, we examined the direct effect and underlying mechanism of the vasomotor action of fenofibrate in porcine retinal arterioles. (arvojournals.org)
  • In a separate subset of arterioles, the effect of augmenting vasomotor tone on CVD was tested using elevated O2 or phenylephrine (PE) in the superfusion solution vs. control. (umsystem.edu)
  • 1 Reactive oxygen species (ROS) have been implicated in the increased vascular reactivity of the renal afferent arterioles to angiotensin II in states of oxidative stress. (ahajournals.org)
  • Interaction between endogenously produced carbon monoxide and nitric oxide in regulation of renal afferent arterioles. (semanticscholar.org)
  • Advective transport of nitric oxide in a mathematical model of the afferent arteriole. (semanticscholar.org)
  • This appears to be due to an impaired synthesis and/or action of nitric oxide (including reduced bioavailability of NO due to increased oxidative stress) and alterations in the metabolism of arachidonic acid to favor an enhanced production of the vasoconstrictor metabolite PGH2 and a reduced production of vasodilator prostaglandins in the arterioles. (alpfmedical.info)
  • Accordingly, we hypothesized that loss of sex hormones impairs afferent arteriole reactivity to ET-1. (springer.com)
  • These data demonstrate that sex does not significantly influence afferent arteriole reactivity to ET receptor activation. (springer.com)
  • Further, we show examples of experiments that can be performed with these arterioles, including agonist-induced constriction and myogenic reactivity. (unr.edu)
  • To study the mechanisms that regulate the contraction of intrapulmonary arteriole SMCs, the contractile and Ca 2+ responses of the arteriole SMCs to 5-hydroxytrypamine (5-HT) and KCl were observed with phase-contrast and scanning confocal microscopy in thin lung slices cut from mouse lungs stiffened with agarose and gelatin. (rupress.org)
  • Arterioles have muscular walls (usually only one to two layers of smooth muscle) and are the primary site of vascular resistance. (wikipedia.org)
  • Arteriolosclerosis is the term specifically used for the hardening of arteriole walls. (wikipedia.org)
  • Walls of the arteriole (brown) are made up of a single layer of endothelial and muscle cells. (fineartamerica.com)
  • Arterioles have thick muscular walls and are the primary site of vascular resistance . (academickids.com)
  • Thus arteriole walls are much thinner than those of arteries. (innerbody.com)
  • RT-PCR assays revealed the expression of both angiotensin II receptor type 1A (AT(1A)) and angiotensin II receptor type 1B (AT(1B)) subtypes in freshly isolated afferent arterioles, while there was very little AT2 receptor expression. (unboundmedicine.com)
  • Abstract -Angiotensin II (Ang II)-induced Ca 2+ signaling was studied in isolated rat renal arterioles using fura-2. (ahajournals.org)
  • Angiotensin II-induced changes in smooth muscle calcium in rat renal arterioles. (semanticscholar.org)
  • Coloured transmission electron micrograph (TEM) of a section through the wall of an arteriole, showing smooth muscle (brown), endothelial cells (green), and an inner and outer lamina (membrane, blue). (sciencephoto.com)
  • Fig. 1 Direct activation of L-type VDCCs in arterioles with BayK increases Ca 2+ events in endothelial cells. (sciencemag.org)
  • A ) Confocal fluorescence images of endothelial cells (ECs) loaded with heparin-Cy5 (yellow) and the corresponding IP 3 R1 fluorescence in the same arteriole (magenta). (sciencemag.org)
  • hands caused by spasms in arterioles (small arteries) of the skin. (britannica.com)
  • their very small branches are arterioles. (britannica.com)
  • Arterioles are small, muscular branches of arteries. (heart.org)
  • Cutaneous arterioles and AVS receive a convergence of vasoconstrictive sympathetic innervation, and vasodilatory small-fiber sensory innervation. (prohealth.com)
  • Also, if such glands are found in close proximity to a thick-walled, medium or small arteriole , it most likely represents an invasive adenocarcinoma. (thefreedictionary.com)
  • Arterioles are small branches of arteries. (gettyimages.es)
  • Therefore, we examined the responses of small intrapulmonary arterioles in lung slices to correlate the Ca 2+ signaling of the SMCs with the contraction. (rupress.org)
  • The major determinant of vascular resistance is small arteriolar (known as resistance arterioles) tone. (hyperleap.com)
  • The contributions of active and passive wall tension to regulation of arteriolar diameters were determined for large (1A), intermediate (2A), and small (3A) arterioles in the small intestine of the anesthetized rat. (elsevier.com)
  • T(a) was ~90% of peak active tension (T(a,peak)) for large through small arterioles, even though absolute T(a) varied by fourfold. (elsevier.com)
  • We hypothesized that in vitro incubation of arterioles of male SHR with estrogen will restore NO-mediated responses by upregulation of endothelial NO synthase. (ahajournals.org)
  • Conclusions -Estrogen, via a receptor-mediated pathway, upregulates endothelial NO synthase gene expression, leading to increased NO production, and restores the regulation of wall shear stress in arterioles of male SHR. (ahajournals.org)
  • 9 17 Our previous studies demonstrated that NO-mediated dilations to agonists 18 19 and flow/shear stress 20 21 are impaired in arterioles of male SHR. (ahajournals.org)
  • Conclusions- In isolated arterioles of PECAM-KO mice activation of eNOS and consequent dilation by agonists is maintained, but the dilation to high temporal gradients of wall shear stress elicited by increases in perfusate flow is reduced. (ahajournals.org)
  • 6 We have shown previously that stepwise increases in perfusate flow, via increases in wall shear stress, elicit substantial dilations of isolated arterioles. (ahajournals.org)
  • In addition to an enhanced response to vasoconstrictor stimuli, arterioles of hypertensive animals exhibit an impaired relaxation in response to a variety of vasodilator stimuli including hypoxia, shear stress, and endothelium-dependent vasodilators, such as acetylcholine (ACh). (alpfmedical.info)
  • This leads to most examiners applying an almost binary approach to grading AVR by stating 2:3 in most cases, whereas in cases of vessels of the same size as 1:1 and retinal arterioles classed as generalised narrow, referred to as 1:2. (thefreedictionary.com)
  • Over recent years, we and others have investigated the signaling pathways underlying the myogenic response in retinal arterioles, with particular emphasis on the involvement of different ion channels expressed in the smooth muscle layer of these vessels. (disease-connect.org)
  • 17 Although we found no effects of PEG-CAT on myogenic contractions in afferent arterioles from normal mice, we investigated the effects of bath addition of H 2 O 2 on basal contractility and myogenic responses to determine its potential role in states of vascular oxidative stress. (ahajournals.org)
  • 1. Measurements of the internal diameters and lengths of branchless segments of mesenteric arterioles of frogs and mice show those geometrically to be cone-shaped, not cylindrical. (ebscohost.com)
  • Two-photon fluorescence microscopy and conscious, restrained optical biosensor mice were used to study smooth muscle Ca 2+ signaling in ear arterioles. (frontiersin.org)
  • In contrast, vasomotion and dynamic Ca 2+ signals were rarely observed in ear arterioles of anesthetized exMLCK biosensor mice. (frontiersin.org)
  • Inhibition of eNOS significantly reduced the initial phase of dilations in arterioles from WT, but not from those of PECAM-KO mice. (ahajournals.org)
  • Our findings suggest that cyclooxygenase-mediated vasoconstrictor prostanoids partly contribute to endothelial dysfunction of visceral adipose arterioles in human obesity. (nih.gov)
  • Human adipose arterioles were incubated in either euglycemic (NG, 5mM) or hyperglycemic (HG, 33mM) buffer for 4 hours. (ahajournals.org)
  • Pulmonary arterioles are a noteworthy exception as they vasodilate in response to high oxygen. (wikipedia.org)
  • These findings are the first in vivo studies to suggest that acute intravascular hemolysis promotes ADP-dependent platelet activation leading to thrombosis in the pre-capillary pulmonary arterioles and that thrombin generation most likely does not play a significant role in the pathogenesis of acute hemolysis-triggered pulmonary thrombosis. (jci.org)
  • At rest, sympathetic nerves constrict the arterioles in muscle. (washington.edu)
  • The image captures the transition of an arteriole as it loses its internal elastic lamina (black arrow). (arkanalabs.com)
  • Arterioles were incubated with the Ca2+ sensitive fluorescence indicator, Fluo 4-AM (10 μM) (Molecular Probes, Invitrogen) at room temperature for 1 hour. (umsystem.edu)
  • Isolated and pressurized retinal arterioles developed basal tone and constricted in a manner dependent on concentration to ET-1. (arvojournals.org)
  • Results indicate that in isolated renal arterioles AP III dilates preconstricted AA but constricts EA that have either not been pretreated or have been preconstricted with other agonists. (physiology.org)
  • For example, atrial natriuretic peptide dilates the afferent arteriole and constricts the efferent arteriole to increase GFR, 1 whereas thromboxane preferentially constricts the afferent arteriole, decreasing GFR. (ahajournals.org)
  • The molecular cornerstone of this mechanism is the capillary endothelial cell inward rectifier K + (Kir2.1) channel, which is activated by neuronal activity-dependent increases in external K + concentration, producing a propagating hyperpolarizing electrical signal that dilates upstream arterioles. (pnas.org)
  • Pharmacological inhibition of cyclooxygenase with indomethacin improved endothelium-dependent vasodilator function of arterioles from visceral fat by twofold (P = 0.01), whereas indomethacin had no effect in the subcutaneous depot. (nih.gov)
  • Fenofibrate elicits mainly endothelium-dependent dilation of retinal arterioles. (arvojournals.org)
  • Impaired relaxation of arterioles to endothelium-dependent vasodilator stimuli such as ACh has also been demonstrated in human hypertensive patients . (alpfmedical.info)