Hyperemia: The presence of an increased amount of blood in a body part or an organ leading to congestion or engorgement of blood vessels. Hyperemia can be due to increase of blood flow into the area (active or arterial), or due to obstruction of outflow of blood from the area (passive or venous).Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.Forearm: Part of the arm in humans and primates extending from the ELBOW to the WRIST.Vasodilation: The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.Coronary Circulation: The circulation of blood through the CORONARY VESSELS of the HEART.Brachial Artery: The continuation of the axillary artery; it branches into the radial and ulnar arteries.Adenosine: 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.Laser-Doppler Flowmetry: A method of non-invasive, continuous measurement of MICROCIRCULATION. The technique is based on the values of the DOPPLER EFFECT of low-power laser light scattered randomly by static structures and moving tissue particulates.Blood Flow Velocity: A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Microcirculation: The circulation of the BLOOD through the MICROVASCULAR NETWORK.Plethysmography: Recording of change in the size of a part as modified by the circulation in it.Endothelium, Vascular: Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.Cerebrovascular Circulation: The circulation of blood through the BLOOD VESSELS of the BRAIN.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Vascular Resistance: 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.Fractional Flow Reserve, Myocardial: The ratio of maximum blood flow to the MYOCARDIUM with CORONARY STENOSIS present, to the maximum equivalent blood flow without stenosis. The measurement is commonly used to verify borderline stenosis of CORONARY ARTERIES.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Nitric Oxide: 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.Coronary Vessels: The veins and arteries of the HEART.Dipyridamole: A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752)Constriction: The act of constricting.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Theophylline: A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3',5'-CYCLIC NUCLEOTIDE PHOSPHODIESTERASE that degrades CYCLIC AMP thus potentiates the actions of agents that act through ADENYLYL CYCLASES and cyclic AMP.NG-Nitroarginine Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.Muscle, Skeletal: 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.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Skin Temperature: The TEMPERATURE at the outer surface of the body.Ketorolac: A pyrrolizine carboxylic acid derivative structurally related to INDOMETHACIN. It is an NSAID and is used principally for its analgesic activity. (From Martindale The Extra Pharmacopoeia, 31st ed)Prostaglandins: 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.omega-N-Methylarginine: A competitive inhibitor of nitric oxide synthetase.Nitric Oxide Synthase: An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.Fingers: Four or five slender jointed digits in humans and primates, attached to each HAND.Blood Circulation: The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.Hippocampus: A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.Urethane: Antineoplastic agent that is also used as a veterinary anesthetic. It has also been used as an intermediate in organic synthesis. Urethane is suspected to be a carcinogen.Nails: The thin, horny plates that cover the dorsal surfaces of the distal phalanges of the fingers and toes of primates.Arterioles: The smallest divisions of the arteries located between the muscular arteries and the capillaries.Vanillic Acid: A flavoring agent. It is the intermediate product in the two-step bioconversion of ferulic acid to vanillin. (J Biotechnol 1996;50(2-3):107-13).Blood-Brain Barrier: Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.Brain Ischemia: Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.Carotid Artery, Common: The two principal arteries supplying the structures of the head and neck. They ascend in the neck, one on each side, and at the level of the upper border of the thyroid cartilage, each divides into two branches, the external (CAROTID ARTERY, EXTERNAL) and internal (CAROTID ARTERY, INTERNAL) carotid arteries.Gerbillinae: A subfamily of the Muridae consisting of several genera including Gerbillus, Rhombomys, Tatera, Meriones, and Psammomys.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Muscle Contraction: A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.Phosphates: Inorganic salts of phosphoric acid.Muscles: Contractile tissue that produces movement in animals.Vibrissae: Stiff hairs projecting from the face around the nose of most mammals, acting as touch receptors.
  • The diagnostic accuracy was independent of vessel, embedded versus core laboratory-generated ECG gating signal, use of intravenous versus intracoronary adenosine to induce hyperemia, and clinical site. (itags.org)
  • We tested the hypothesis that the attenuated cerebral blood flow (CBF) response to whisker stimulation seen after NO synthase (NOS) inhibition requires 20-HETE synthesis and that the ability of an epoxyeicosatrienoic acids (EETs) antagonist to reduce the CBF response is blunted after NOS inhibition but restored with simultaneous blockade of 20-HETE synthesis. (elsevier.com)
  • Myocardial blood flow at rest and during adenosine-induced hyperemia was quantified by contrast-enhanced magnetic resonance imaging, to study the relation between regional flow and function after multivariable adjustment for age, gender, body mass index, left ventricular mass, and traditional risk factors. (ahajournals.org)
  • Using myocardial contrast echocardiography, myocardial blood flow (MBF) and microcirculatory variables were assessed at rest, during adenosine-induced hyperemia, and after cold pressor test-induced sympathetic stimulation. (biomedsearch.com)
  • Folkow, B., Halicka, H. D.: A comparison between 'red' and 'white' muscle with respect to blood supply, capillary surface area and oxygen uptake during rest and exercise. (springer.com)
  • We demonstrate that the plasma membrane phospholipid, PIP 2 , is fundamental to sustaining the activity of inwardly rectifying potassium channels-the molecular feature that allows capillary endothelial cells to sense ongoing neuronal activity and trigger an increase in local blood flow. (pnas.org)
  • 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)
  • Sickle-cell anemia is associated with blood vessel sludging, altered blood flow and blood vessel diameter, and capillary micro-haemorrhages . (wikipedia.org)
  • We will explore whether the post-occlusive reactive hyperemia in the forearm is potentiated, because during ischaemia, more adenosine is formed in these subjects. (bioportfolio.com)
  • The results demonstrate that the incomplete restoration of blood flow was indeed the result of a sympathetic vasoconstrictor influence in the forearm microcirculation, as the non-selective α-adrenoceptor antagonist phentolamine facilitated blood flow recovery to pre-inflation levels. (frontiersin.org)
  • Forearm blood flow (ml/min/100 ml) at rest and during rhythmic handgrip exercise and after transient arterial occlusion was determined by strain gauge plethysmography before and 4 h and six weeks after combined administration of enalapril with either aspirin, ifetroban or placebo in a multicenter, double-blind, randomized trial of 62 patients with mild to moderate heart failure. (onlinejacc.org)
  • Before randomization, forearm hemodynamics were similar in the three treatment groups except for increased resting forearm blood flow and decreased resting forearm vascular resistance in the aspirin group when compared with the placebo group. (onlinejacc.org)
  • After combined administration of enalapril and study drug for 4 h and six weeks, changes from prerandomization values of mean arterial pressure, forearm blood flow and forearm vascular resistance at rest, during handgrip exercise and after transient arterial occlusion did not differ among the three treatment groups. (onlinejacc.org)
  • Analysis of the blood flow velocity in the forearm was made in comparison to established methods of estimating endothelial function, clinical markers of cardiovascular risk, the Framingham risk score and global atherosclerosis determined by whole body magnetic resonance angiography. (diva-portal.org)
  • Using laser Doppler velocimetry, we measured the vessel diameter and blood velocity simultaneously and calculated the retinal blood flow (RBF) in feline first-order retinal arterioles. (arvojournals.org)
  • B ) Blood flow increase to flicker stimulation (black bar) measured at the rim of the optic disc in cats with laser Doppler flowmetry. (nih.gov)
  • Öberg, "Evaluation of a laser doppler flowmeter foi measurement of tissue blood flow," IEEE Transactions on Biomedical Engineering , vol. 27, no. 10, pp. 597-604, 1980. (hindawi.com)
  • A laser Doppler flowmeter was used to assess blood flow changes in habitual smokers, as compared with nonsmokers, where members of both groups were young and healthy. (nih.gov)
  • Over the next four hours, blood samples were taken and the researchers used Doppler laser to measure endothelial responses to sudden changes in blood flow, which were produced by inflating and then deflating a blood pressure cuff. (bio-medicine.org)
  • METHODS: Skin perfusion, measured by laser Doppler flowmetry, was assessed at rest and during reactive hyperemia. (uzh.ch)
  • CONCLUSIONS: Reactive hyperemia of the skin microcirculation can be easily and reproducibly assessed by laser Doppler flowmetry. (uzh.ch)
  • Arterial pressure, heart rate, cardiac output determined by transthoracic impedance, transcutaneous oxygen (tcPO 2 ) and carbon dioxide (tcPCO 2 ) pressures, and microcirculatory blood flow determined by laser Doppler flowmetry at rest and during a reactive hyperaemia challenge were measured before sedation (NS period), one hour after midazolam infusion (H period), and one hour after midazolam-sufentanil infusion (HS period). (springer.com)
  • A transmediastinal artery persists in ≤50% of patients and will appear as a prominent hypoechoic band within the testicle, with blood flow in the opposite direction of the recurrent rami arteries with Doppler imaging. (appliedradiology.com)
  • Topical Zangrado (1%) was assessed for anti-pruretic actions in the 5-HT-induced scratching model in rats and evaluated in capsaicin-induced gastric hyperemia as measured by laser doppler flow. (biomedcentral.com)
  • Plasmodium falciparum parasitaemia in the first half of pregnancy, uterine and umbilical artery blood flow, and foetal growth: a longitudinal Doppler ultrasound study. (ebscohost.com)
  • We further show that chemical factors released in the brain, including those associated with neuronal activity, cause changes in the levels of PIP 2 , thereby altering endothelial potassium channel signaling and controlling cerebral blood flow. (pnas.org)
  • Brain capillaries play a critical role in sensing neural activity and translating it into dynamic changes in cerebral blood flow to serve the metabolic needs of the brain. (pnas.org)
  • Endothelial PIP 2 levels would therefore shape the extent of retrograde signaling and modulate cerebral blood flow. (pnas.org)
  • Transient MCAO was induced during either isoflurane or ketamine/xylazine (ket/xyl) anesthesia with simultaneously measurement of cerebral blood flow (CBF) in 60 male Wistar rats (380-420 g). (springer.com)
  • Study of changes in cerebral blood flow and cerebrovascular reactivity at the period of late postnatal ontogenesis. (ebscohost.com)
  • The article reports on the study of modifications in cerebral blood flow and cerebrovascular responsiveness during late postnatal ontogenesis. (ebscohost.com)
  • Functional neuroimaging, such as fMRI, is based on coupling neuronal activity and accompanying changes in cerebral blood flow (CBF) and metabolism. (pnas.org)
  • Numerous studies over the past decade have implicated modulation of ion channels by several diverse stimuli as one of the principal transduction processes responsible for defining the activation state of cerebral arteriolar muscle and thereby adjusting blood flow to meet metabolic demand. (ahajournals.org)
  • n = 4 per group) animals, suggesting a dichotomous regulatory role for each of these subunits in coronary metabolic hyperemia. (ahajournals.org)
  • In conclusion, findings suggest that KV1.5 in CVSM associates with KVβ1.1 and KVβ2 subunits, which differentially modulate channel function to fine tune metabolic hyperemia. (ahajournals.org)
  • Consequently allowing blood flow to meet and match the metabolic demand of the tissue and prevents a mismatch between O2-demand O2-supply. (wikipedia.org)
  • 6) The brain has numerous physiological mechanisms to maintain blood flow to meet metabolic demand, without jeopardising the delicate balance of factors that maintain ICP. (thefreelibrary.com)
  • The drop in blood pressure following acute exercise, called post-exercise hypotension (PEH), is seen in both healthy people and hypertensives, and persists for a few hours. (news-medical.net)
  • Conclusions- Thus, lower reactive hyperemia is associated with increased cardiovascular risk in patients with peripheral arterial disease. (ahajournals.org)
  • CONCLUSIONS: In otherwise healthy subjects who are not subjected to surgical stimulation, MBF at rest and after sympathetic stimulation is preserved during sevoflurane anesthesia despite a decrease in myocardial blood volume. (biomedsearch.com)
  • 2-4 Close relations between reduced myocardial blood flow (MBF) and regional wall motion abnormalities have been demonstrated in patients with coronary artery disease by contrast ventriculography, 5 nuclear imaging, 6 echocardiography, 7 and magnetic resonance imaging (MRI) 8,9 at rest and during stress induced by exercise and pharmacological stimulation. (ahajournals.org)
  • Relative myocardial blood volume (rBV), exchange flow velocity (β), myocardial blood flow (MBF), MBF reserve (MFR) and endocardial-to-subepicardial (endo-to-epi) MBF ratio were measured from the steady state and contrast replenishment time-intensity curves. (bmj.com)
  • Statins enhance postischemic hyperemia in the skin circulation of hypercholesterolemic patients: a monitoring test of endothelial dysfunction for clinical practice? (uzh.ch)
  • Serum creatinine and potassium[K+] were measured monthly, AIC levels every 3 months and CIMT by ultrasound and endothelial function by post hyperemia and nitroglycerine (NTG) - induced peripheral artery tonometry (PAT) via finger plethysmography every six months. (clinicaltrials.gov)
  • Using high-resolution ultrasound, we examined the role of endothelial mediators in radial artery dilatation in response to transient (short period of reactive hyperemia) and sustained (prolonged period of reactive hyperemia, hand warming, or an incremental infusion of acetylcholine into the distal radial artery) hyperemia. (ahajournals.org)
  • These data suggest heterogeneity of endothelial responses to blood flow that are dependent on the characteristics of the flow stimulus. (ahajournals.org)
  • These data suggest heterogeneity of the endothelial response to blood flow, whereby the physical characteristics of the flow stimulus might be important in determining the mechanism of the subsequent dilatation. (ahajournals.org)
  • In contrast, in the presence of a flow-limiting artery stenosis the sympathetic vasoconstrictor influence may interfere with autoregulation of muscle blood flow, thereby aggravating tissue hypoperfusion. (frontiersin.org)
  • Recent research has suggested that the locally produced vasodilators may be acting in a redundant manner, in which the antagonism of one dilator, be it pharmacologically or pathologically, may be compensated for by another in order to preserve blood flow to tissue. (wikipedia.org)
  • Conversely, when a tissue is less metabolically active, it produces fewer metabolites which are simply washed away in blood flow. (wikipedia.org)
  • Reactive hyperaemia often occurs as a consequence of Raynaud's phenomenon, where the vasospasm in the vasculature leads to ischaemia and necrosis of tissue and thus a subsequent increase in blood flow to remove the waste products and clear up cell debris. (wikipedia.org)
  • Reactive hyperemia tests showed increased tissue oxygenation was increased after exercise with placebo use but not after the mouthwash. (news-medical.net)
  • MBF was calculated from the relative myocardial blood volume multiplied by its exchange frequency (β) divided by myocardial tissue density (ρT), which was set at 1.05 g·mL(-1). (biomedsearch.com)
  • Brain tissue, blood volume and CSF are the three main elements contributing to the generation of ICP. (thefreelibrary.com)
  • The volume of brain tissue in a healthy adult is constant, while volumes of blood and CSF within the cranial cavity are tightly controlled to prevent fluctuations in ICP. (thefreelibrary.com)
  • In each case, increasing levels leads to increased blood flow in the local tissue. (washington.edu)
  • The distance that oxygen can diffuse from blood into oxygen-consuming tissue is limited. (frontiersin.org)
  • The blood supply to the palpebral conjunctiva (the eyelid) is derived from the external carotid artery . (wikipedia.org)
  • Carotid artery stent placement improves blood flow in the affected hemisphere in symptomatic and asymptomatic patients. (ajnr.org)
  • Denes A, Ferenczi S, Kovacs KJ (2011) Systemic inflammatory challenges compromise survival after experimental stroke via augmenting brain inflammation, blood- brain barrier damage and brain oedema independently of infarct size. (springer.com)
  • Wondering if anyone out there in physiology-land can offer a layman's explanation of the difference between a hematoma and hyperemia. (biology-online.org)
  • Given that neuronal metabolism relies almost exclusively on oxidative metabolism, all normal function, from control of motor activity to cognitive ability and memory acquisition, requires adequate delivery of oxygenated blood. (ahajournals.org)
  • Using mouthwash reduces the activity of this pathway, and some studies have shown that resting systolic blood pressure goes up after mouthwash is used for a few days. (news-medical.net)