A response by the BARORECEPTORS to increased BLOOD PRESSURE. Increased pressure stretches BLOOD VESSELS which activates the baroreceptors in the vessel walls. The net response of the CENTRAL NERVOUS SYSTEM is a reduction of central sympathetic outflow. This reduces blood pressure both by decreasing peripheral VASCULAR RESISTANCE and by lowering CARDIAC OUTPUT. Because the baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.
The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.
An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.
The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure.
The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).
The ENTERIC NERVOUS SYSTEM; PARASYMPATHETIC NERVOUS SYSTEM; and SYMPATHETIC NERVOUS SYSTEM taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the CENTRAL NERVOUS SYSTEM, especially the HYPOTHALAMUS and the SOLITARY NUCLEUS, which receive information relayed from VISCERAL AFFERENTS.
An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
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.
GRAY MATTER located in the dorsomedial part of the MEDULLA OBLONGATA associated with the solitary tract. The solitary nucleus receives inputs from most organ systems including the terminations of the facial, glossopharyngeal, and vagus nerves. It is a major coordinator of AUTONOMIC NERVOUS SYSTEM regulation of cardiovascular, respiratory, gustatory, gastrointestinal, and chemoreceptive aspects of HOMEOSTASIS. The solitary nucleus is also notable for the large number of NEUROTRANSMITTERS which are found therein.
Cardiac arrhythmias that are characterized by excessively slow HEART RATE, usually below 50 beats per minute in human adults. They can be classified broadly into SINOATRIAL NODE dysfunction and ATRIOVENTRICULAR BLOCK.
Forced expiratory effort against a closed GLOTTIS.
The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)
The HEART and the BLOOD VESSELS by which BLOOD is pumped and circulated through the body.
Sense of awareness of self and of the environment.
The posture of an individual lying face up.
A nicotinic antagonist that has been used as a ganglionic blocker in hypertension, as an adjunct to anesthesia, and to induce hypotension during surgery.
The vessels carrying blood away from the heart.
Drugs used to cause constriction of the blood vessels.
An abnormal response to a stimulus applied to the sensory components of the nervous system. This may take the form of increased, decreased, or absent reflexes.
Processes and properties of the CARDIOVASCULAR SYSTEM as a whole or of any of its parts.
The hollow, muscular organ that maintains the circulation of the blood.
External decompression applied to the lower body. It is used to study orthostatic intolerance and the effects of gravitation and acceleration, to produce simulated hemorrhage in physiologic research, to assess cardiovascular function, and to reduce abdominal stress during childbirth.
A standard and widely accepted diagnostic test used to identify patients who have a vasodepressive and/or cardioinhibitory response as a cause of syncope. (From Braunwald, Heart Disease, 7th ed)
The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.
A significant drop in BLOOD PRESSURE after assuming a standing position. Orthostatic hypotension is a finding, and defined as a 20-mm Hg decrease in systolic pressure or a 10-mm Hg decrease in diastolic pressure 3 minutes after the person has risen from supine to standing. Symptoms generally include DIZZINESS, blurred vision, and SYNCOPE.
The neural systems which act on VASCULAR SMOOTH MUSCLE to control blood vessel diameter. The major neural control is through the sympathetic nervous system.
Agents having as their major action the interruption of neural transmission at nicotinic receptors on postganglionic autonomic neurons. Because their actions are so broad, including blocking of sympathetic and parasympathetic systems, their therapeutic use has been largely supplanted by more specific drugs. They may still be used in the control of blood pressure in patients with acute dissecting aortic aneurysm and for the induction of hypotension in surgery.
Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.
Posture while lying with the head lower than the rest of the body. Extended time in this position is associated with temporary physiologic disturbances.
Abnormally rapid heartbeat, usually with a HEART RATE above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia.
The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot.
The position or attitude of the body.
An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness.
Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.
Diseases of the parasympathetic or sympathetic divisions of the AUTONOMIC NERVOUS SYSTEM; which has components located in the CENTRAL NERVOUS SYSTEM and PERIPHERAL NERVOUS SYSTEM. Autonomic dysfunction may be associated with HYPOTHALAMIC DISEASES; BRAIN STEM disorders; SPINAL CORD DISEASES; and PERIPHERAL NERVOUS SYSTEM DISEASES. Manifestations include impairments of vegetative functions including the maintenance of BLOOD PRESSURE; HEART RATE; pupil function; SWEATING; REPRODUCTIVE AND URINARY PHYSIOLOGY; and DIGESTION.
The blood pressure in the central large VEINS of the body. It is distinguished from peripheral venous pressure which occurs in an extremity.
The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.
The removal or interruption of some part of the autonomic nervous system for therapeutic or research purposes.
Diseases of the tenth cranial nerve, including brain stem lesions involving its nuclei (solitary, ambiguus, and dorsal motor), nerve fascicles, and intracranial and extracranial course. Clinical manifestations may include dysphagia, vocal cord weakness, and alterations of parasympathetic tone in the thorax and abdomen.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.
Drugs that mimic the effects of stimulating postganglionic adrenergic sympathetic nerves. Included here are drugs that directly stimulate adrenergic receptors and drugs that act indirectly by provoking the release of adrenergic transmitters.
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.
Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.
Plethysmographic determination in which the intensity of light reflected from the skin surface and the red cells below is measured to determine the blood volume of the respective area. There are two types, transmission and reflectance.
Drugs used to cause dilation of the blood vessels.
A change in cardiovascular function resulting in a reduction in BLOOD VOLUME, and reflex DIURESIS. It occurs frequently after actual or simulated WEIGHTLESSNESS.
Double-layered inflatable suits which, when inflated, exert pressure on the lower part of the wearer's body. The suits are used to improve or stabilize the circulatory state, i.e., to prevent hypotension, control hemorrhage, and regulate blood pressure. The suits are also used by pilots under positive acceleration.
The rhythmical expansion and contraction of an ARTERY produced by waves of pressure caused by the ejection of BLOOD from the left ventricle of the HEART as it contracts.
The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
An irregularly shaped cavity in the RHOMBENCEPHALON, located between the MEDULLA OBLONGATA; the PONS; and the isthmus in front, and the CEREBELLUM behind. It is continuous with the central canal of the cord below and with the CEREBRAL AQUEDUCT above, and through its lateral and median apertures it communicates with the SUBARACHNOID SPACE.
Nerve fibers which project from sympathetic ganglia to synapses on target organs. Sympathetic postganglionic fibers use norepinephrine as transmitter, except for those innervating eccrine sweat glands (and possibly some blood vessels) which use acetylcholine. They may also release peptide cotransmitters.
Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.
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.
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.
Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.
The delivery of a drug into a fluid-filled cavity of the brain.
The blood pressure in the ARTERIES. It is commonly measured with a SPHYGMOMANOMETER on the upper arm which represents the arterial pressure in the BRACHIAL ARTERY.
A degenerative disease of the AUTONOMIC NERVOUS SYSTEM that is characterized by idiopathic ORTHOSTATIC HYPOTENSION and a greatly reduced level of CATECHOLAMINES. No other neurological deficits are present.
A strain of Rattus norvegicus with elevated blood pressure used as a model for studying hypertension and stroke.
Analogs and derivatives of atropine.
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.
The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).
Injections into the cerebral ventricles.
Loss of consciousness due to a reduction in blood pressure that is associated with an increase in vagal tone and peripheral vasodilation.
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.
The dilatation of the aortic wall behind each of the cusps of the aortic valve.
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)
Abnormally low BLOOD PRESSURE that can result in inadequate blood flow to the brain and other vital organs. Common symptom is DIZZINESS but greater negative impacts on the body occur when there is prolonged depravation of oxygen and nutrients.
The part of a human or animal body connecting the HEAD to the rest of the body.
The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.
A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.
The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.
Transmission of the readings of instruments to a remote location by means of wires, radio waves, or other means. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Nerve fibers liberating catecholamines at a synapse after an impulse.
The removal of secretions, gas or fluid from hollow or tubular organs or cavities by means of a tube and a device that acts on negative pressure.
An antagonist of ANGIOTENSIN TYPE 1 RECEPTOR with antihypertensive activity due to the reduced pressor effect of ANGIOTENSIN II.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).

Effects of amlodipine on sympathetic nerve traffic and baroreflex control of circulation in heart failure. (1/1596)

Short-acting calcium antagonists exert a sympathoexcitation that in heart failure further enhances an already elevated sympathetic activity. Whether this is also the case for long-acting formulations is not yet established, despite the prognostic importance of sympathetic activation in heart failure. It is also undetermined whether in this condition long-acting calcium antagonists favorably affect a mechanism potentially responsible for the sympathetic activation, ie, the baroreflex impairment. In 28 heart failure patients (NYHA functional class II) under conventional treatment we measured plasma norepinephrine and efferent postganglionic muscle sympathetic nerve activity (microneurography) at rest and during arterial baroreceptor stimulation and deactivation induced by stepwise intravenous infusions of phenylephrine and nitroprusside, respectively. Measurements were performed at baseline and after 8 weeks of daily oral amlodipine administration (10 mg/d, 14 patients) or before and after an 8-week period without calcium antagonist administration (14 patients). Amlodipine caused a small and insignificant blood pressure reduction. Heart rate, left ventricular ejection fraction, and plasma renin and aldosterone concentrations were not affected. This was the case also for plasma norepinephrine (from 2.43+/-0.41 to 2.50+/-0.34 nmol/L, mean+/-SEM), muscle sympathetic nerve activity (from 54.4+/-5.9 to 51.0+/-4.3 bursts/min), and arterial baroreflex responses. No change in the above-mentioned variables was seen in the control group. Thus, in mild heart failure amlodipine treatment does not adversely affect sympathetic activity and baroreflex control of the heart and sympathetic tone. This implies that in this condition long-acting calcium antagonists can be administered without untoward neurohumoral effects anytime conventional treatment needs to be complemented by drugs causing additional vasodilatation.  (+info)

A method for determining baroreflex-mediated sympathetic and parasympathetic control of the heart in pregnant and non-pregnant sheep. (2/1596)

1. The cardiac baroreflex was measured in four non-pregnant and six pregnant ewes before and during beta-adrenoreceptor blockade with propranolol and before and during vagal blockade with atropine. Arterial pressure was raised by phenylephrine and lowered by sodium nitroprusside. The relationships between mean arterial pressure (MAP) and heart rate (HR), between MAP and heart rate variability (HRV) measured as the coefficient of variation (c.v.) of the mean pulse interval (PI), and between MAP and HRV measured by power spectral analysis were determined. 2. The MAP-HR relationship showed that in pregnant ewes the gain of the cardiac baroreflex was reduced when compared with non-pregnant ewes. Threshold and saturation pressures were higher, maximum achievable HR was lower and there was a decrease in the operating range. 3. V-shaped relationships were obtained between MAP and HRV (measured as the c.v. of PI) and between MAP and power spectral density in the frequency range 0.04-0. 08 Hz. Using selective autonomic blockade the negative, or downward, slope of the V shape was shown to be a measure of baroreceptor-induced, sympathetically mediated effects on HRV. The upward, or positive, slope of the V shape was a measure of baroreceptor-induced, vagally mediated effects. Similar results were also obtained from the cardiac power spectrum, but it was less sensitive. The MAP at which the two slopes intersected was the same as the resting MAP. 4. In pregnant ewes, the slope of the downward limb of the V-shaped relationship between HRV (when measured as the c.v. of PI) and MAP was less than in non-pregnant ewes. 5. The relationship between MAP and the coefficient of variation of the mean pulse interval can therefore be used to measure the degree to which baroreceptor-induced sympathetic and parasympathetic activity affects the heart. 6. The resting MAP is the pressure at which the net effect of these sympathetic and parasympathetic influences on the heart is at a minimum. Studies of both the MAP-HR and MAP-HRV relationships in pregnant and non-pregnant sheep show that in pregnant sheep, there is attenuation of baroreceptor-mediated sympathetic effects on the heart.  (+info)

Vasopressin V2 receptor enhances gain of baroreflex in conscious spontaneously hypertensive rats. (3/1596)

The aim of the present study was to determine the receptor subtype involved in arginine vasopressin (AVP)-induced modulation of baroreflex function in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats using novel nonpeptide AVP V1- and V2-receptor antagonists. Baroreceptor heart rate (HR) reflex was investigated in both SHR and WKY rats which were intravenously administered the selective V1- and V2-receptor antagonists OPC-21268 and OPC-31260, respectively. Baroreflex function was assessed by obtaining alternate pressor and depressor responses to phenylephrine and sodium nitroprusside, respectively, to construct baroreflex curves. In both SHR and WKY rats baroreflex activity was tested before and after intravenous administration of vehicle (20% DMSO), OPC-21268 (10 mg/kg), and OPC-31260 (1 and 10 mg/kg). Vehicle did not significantly alter basal mean arterial pressure (MAP) and HR values or baroreflex function in SHR or WKY rats. The V1-receptor antagonist had no significant effect on resting MAP or HR values or on baroreflex parameters in both groups of rats, although this dose was shown to significantly inhibit the pressor response to AVP (5 ng iv; ANOVA, P < 0.05). In SHR but not WKY rats the V2-receptor antagonist significantly attenuated the gain (or slope) of the baroreflex curve (to 73 +/- 3 and 79 +/- 7% of control for 1 and 10 mg/kg, respectively), although AVP-induced pressor responses were also attenuated with the higher dose of the V2-receptor antagonist. These findings suggest that AVP tonically enhances baroreflex function through a V2 receptor in the SHR.  (+info)

Cardiac baroreflex during the postoperative period in patients with hypertension: effect of clonidine. (4/1596)

BACKGROUND: Patients with essential hypertension show altered baroreflex control of heart rate, and during the perioperative period they demonstrate increased circulatory instability. Clonidine has been shown to reduce perioperative circulatory instability. This study documents changes in measures of heart rate control after surgery in patients with essential hypertension and determines the effects of clonidine on postoperative heart rate control in these patients. METHODS: Using a randomized double-blind placebo-controlled design, 20 patients with essential hypertension (systolic pressure >160 mm Hg or diastolic pressure >95 mm Hg for > or =1 yr) were assigned to receive clonidine (or placebo), 6 microg/kg orally 120 min before anesthesia and 3 microg/kg intravenously over 60 min before the end of surgery. The spontaneous baroreflex ("sequence") technique and analysis of heart rate variability were used to quantify control of heart rate at baseline, before induction of anesthesia, and 1 and 3 h postoperatively. RESULTS: Baroreflex slope and heart rate variability were reduced postoperatively in patients given placebo but not those given clonidine. Clonidine resulted in greater postoperative baroreflex slope and power at all frequency ranges compared with placebo (4.9+/-2.9 vs. 2.2+/-2.1 ms/mm Hg for baroreflex slope, 354+/-685 vs. 30+/-37 ms2/Hz for high frequency variability). Clonidine also resulted in lower concentrations of catecholamine, decreased mean heart rate and blood pressure, and decreased perioperative tachycardia and hypertension. CONCLUSIONS: Patients with hypertension exhibit reduced heart rate control during the recovery period after elective surgery. Clonidine prevents this reduction in heart rate control. This may represent a basis for the improved circulatory stability seen with perioperative administration of clonidine.  (+info)

Hypoxia inhibits baroreflex vagal bradycardia via a central action in anaesthetized rats. (5/1596)

It is known that arterial baroreflexes are suppressed in stressful conditions. The present study was designed to determine whether and how hypoxia affects arterial baroreflexes, especially the heart rate component, baroreflex vagal bradycardia. In chloralose-urethane-anaesthetized rats, baroreflex vagal bradycardia was evoked by electrical stimulation of the aortic depressor nerve, and the effect of 15 s inhalation of hypoxic gas (4% O2) was studied. Inhalation of hypoxic gas was found to inhibit baroreflex vagal bradycardia. The inhibition persisted after bilateral transection of the carotid sinus nerve. Cervical vagus nerves were cut bilaterally and their peripheral cut ends were stimulated to provoke vagal bradycardia of peripheral origin so as to determine whether hypoxia could inhibit vagal bradycardia by acting on a peripheral site. In contrast to baroreflex vagal bradycardia, the vagus-induced bradycardia was not affected by hypoxic gas inhalation. It is concluded that baroreflex vagal bradycardia is inhibited by hypoxia and the inhibition is largely mediated by its direct central action.  (+info)

Prognostic value of nocturnal Cheyne-Stokes respiration in chronic heart failure. (6/1596)

BACKGROUND: Nocturnal Cheyne-Stokes respiration (CSR) occurs frequently in patients with chronic heart failure (CHF), and it may be associated with sympathetic activation. The aim of the present study was to evaluate whether CSR could affect prognosis in patients with CHF. METHODS AND RESULTS: Sixty-two CHF patients with left ventricular ejection fraction /=30/h and left atria >/=25 cm2. CONCLUSIONS: The AHI is a powerful independent predictor of poor prognosis in clinically stable patients with CHF. The presence of an AHI >/=30/h adds prognostic information compared with other clinical, echocardiographic, and autonomic data and identifies patients at very high risk for subsequent cardiac death.  (+info)

The rostral ventrolateral medulla mediates the sympathoactivation produced by chemical stimulation of the rat nasal mucosa. (7/1596)

1. We sought to outline the brainstem circuit responsible for the increase in sympathetic tone caused by chemical stimulation of the nasal passages with ammonia vapour. Experiments were performed in alpha-chloralose-anaesthetized, paralysed and artificially ventilated rats. 2. Stimulation of the nasal mucosa increased splanchnic sympathetic nerve discharge (SND), elevated arterial blood pressure (ABP), raised heart rate slightly and inhibited phrenic nerve discharge. 3. Bilateral injections of the broad-spectrum excitatory amino acid receptor antagonist kynurenate (Kyn) into the rostral part of the ventrolateral medulla (RVLM; rostral C1 area) greatly reduced the effects of nasal mucosa stimulation on SND (-80 %). These injections had no effect on resting ABP, resting SND or the sympathetic baroreflex. 4. Bilateral injections of Kyn into the ventrolateral medulla at the level of the obex (caudal C1 area) or into the nucleus tractus solitarii (NTS) greatly attenuated the baroreflex and significantly increased the baseline levels of both SND and ABP. However they did not reduce the effect of nasal mucosa stimulation on SND. 5. Single-unit recordings were made from 39 putative sympathoexcitatory neurons within the rostral C1 area. Most neurons (24 of 39) were activated by nasal mucosa stimulation (+65.8 % rise in discharge rate). Responding neurons had a wide range of conduction velocities and included slow-conducting neurons identified previously as C1 cells. The remaining putative sympathoexcitatory neurons were either unaffected (n = 8 neurons) or inhibited (n = 7) during nasal stimulation. We also recorded from ten respiratory-related neurons, all of which were silenced by nasal stimulation. 6. In conclusion, the sympathoexcitatory response to nasal stimulation is largely due to activation of bulbospinal presympathetic neurons within the RVLM. We suggest that these neurons receive convergent and directionally opposite polysynaptic inputs from arterial baroreceptors and trigeminal afferents. These inputs are integrated within the rostral C1 area as opposed to the NTS or the caudal C1 area.  (+info)

Investigating feed-forward neural regulation of circulation from analysis of spontaneous arterial pressure and heart rate fluctuations. (8/1596)

BACKGROUND: Analysis of spontaneous fluctuations in systolic arterial pressure (SAP) and pulse interval (PI) reveals the occurrence of sequences of consecutive beats characterized by SAP and PI changing in the same (+PI/+SAP and -PI/-SAP) or opposite (-PI/+SAP and +PI/-SAP) direction. Although the former reflects baroreflex regulatory mechanisms, the physiological meaning of -PI/+SAP and +PI/-SAP is unclear. We tested the hypothesis that -PI/+SAP and +PI/-SAP "nonbaroreflex" sequences represent a phenomenon modulated by the autonomic nervous system reflecting a feed-forward mechanism of cardiovascular regulation. METHODS AND RESULTS: We studied anesthetized rabbits before and after (1) complete autonomic blockade (guanethidine+propranolol+atropine, n=13; CAB), (2) sympathetic blockade (guanethidine+propranolol, n=15; SB), (3) parasympathetic blockade (atropine, n=16), (4) sinoaortic denervation (n=10; SAD), and (5) controlled respiration (n=10; CR). Nonbaroreflex sequences were defined as >/=3 beats in which SAP and PI of the following beat changed in the opposite direction. CAB reduced the number of nonbaroreflex sequences (19. 1+/-12.3 versus 88.7+/-36.6, P<0.05), as did SB (25.3+/-11.7 versus 84.6+/-23.9, P<0.001) and atropine (11.2+/-6.8 versus 94.1+/-32.4, P<0.05). SB concomitantly increased baroreflex sensitivity (1.18+/-0. 11 versus 0.47+/-0.09 ms/mm Hg, P<0.01). SAD and CR did not significantly affect their occurrence. CONCLUSIONS: These results suggest that nonbaroreflex sequences represent the expression of an integrated, neurally mediated, feed-forward type of short-term cardiovascular regulation able to interact dynamically with the feedback mechanisms of baroreflex origin in the control of heart period.  (+info)

* Heart block: A condition where the electrical signals that control the heart's rhythm are blocked or delayed, leading to a slow heart rate.
* Sinus node dysfunction: A condition where the sinus node, which is responsible for setting the heart's rhythm, is not functioning properly, leading to a slow heart rate.
* Medications: Certain medications, such as beta blockers, can slow down the heart rate.
* Heart failure: In severe cases of heart failure, the heart may become so weak that it cannot pump blood effectively, leading to a slow heart rate.
* Electrolyte imbalance: An imbalance of electrolytes, such as potassium or magnesium, can affect the heart's ability to function properly and cause a slow heart rate.
* Other medical conditions: Certain medical conditions, such as hypothyroidism (an underactive thyroid) or anemia, can cause bradycardia.

Bradycardia can cause symptoms such as:

* Fatigue
* Weakness
* Dizziness or lightheadedness
* Shortness of breath
* Chest pain or discomfort

In some cases, bradycardia may not cause any noticeable symptoms at all.

If you suspect you have bradycardia, it is important to consult with a healthcare professional for proper diagnosis and treatment. They may perform tests such as an electrocardiogram (ECG) or stress test to determine the cause of your slow heart rate and develop an appropriate treatment plan. Treatment options for bradycardia may include:

* Medications: Such as atropine or digoxin, to increase the heart rate.
* Pacemakers: A small device that is implanted in the chest to help regulate the heart's rhythm and increase the heart rate.
* Cardiac resynchronization therapy (CRT): A procedure that involves implanting a device that helps both ventricles of the heart beat together, improving the heart's pumping function.

It is important to note that bradycardia can be a symptom of an underlying condition, so it is important to address the underlying cause in order to effectively treat the bradycardia.

Examples of abnormal reflexes include:

1. Overactive reflexes: Reflexes that are too strong or exaggerated, such as an oversensitive knee jerk reflex.
2. Underactive reflexes: Reflexes that are too weak or diminished, such as a decreased tendon reflex in the arm.
3. Delayed reflexes: Reflexes that take longer than expected to occur, such as a delayed deep tendon reflex.
4. Abnormal reflex arc: A reflex arc that is not normal or expected for the situation, such as a spastic reflex arc.
5. Reflexes that are out of proportion to the stimulus: Such as an excessive or exaggerated reflex response to a mild stimulus.
6. Reflexes that occur in the absence of a stimulus: Such as a spontaneous reflex.
7. Reflexes that do not resolve: Such as a persistent reflex.
8. Reflexes that are painful or uncomfortable: Such as an abnormal rectal reflex.

It's important to note that not all abnormal reflexes are necessarily indicative of a serious medical condition, but they should be evaluated by a healthcare professional to determine the underlying cause and appropriate treatment.

There are several possible causes of orthostatic hypotension, including:

1. Deconditioning: This is a common cause of orthostatic hypotension in older adults who have been bedridden or hospitalized for prolonged periods.
2. Medication side effects: Certain medications, such as beta blockers and vasodilators, can cause orthostatic hypotension as a side effect.
3. Heart conditions: Conditions such as heart failure, arrhythmias, and structural heart defects can lead to orthostatic hypotension.
4. Neurological disorders: Certain neurological disorders, such as Parkinson's disease, multiple sclerosis, and stroke, can cause orthostatic hypotension.
5. Vasomotor instability: This is a condition where the blood vessels constrict or dilate rapidly, leading to a drop in blood pressure.
6. Anemia: A low red blood cell count can lead to a decrease in oxygen delivery to the body's tissues, causing orthostatic hypotension.
7. Dehydration: Dehydration can cause a drop in blood volume and lead to orthostatic hypotension.
8. Hypovolemia: This is a condition where there is a low volume of blood in the body, leading to a drop in blood pressure.
9. Sepsis: Sepsis can cause vasodilation and lead to orthostatic hypotension.
10. Other causes: Other causes of orthostatic hypotension include adrenal insufficiency, thyroid disorders, and certain genetic conditions.

Symptoms of orthostatic hypotension may include:

* Dizziness or lightheadedness
* Fainting
* Blurred vision
* Nausea and vomiting
* Headaches
* Fatigue
* Weakness
* Confusion

If you experience any of these symptoms, it is important to seek medical attention as soon as possible. Your healthcare provider can perform a physical examination and order diagnostic tests to determine the underlying cause of your orthostatic hypotension. Treatment will depend on the specific cause, but may include medications to raise blood pressure, fluid replacement, and addressing any underlying conditions.

There are several types of tachycardia, including:

1. Sinus tachycardia: This is the most common type and is caused by an increase in the rate of the normal sinus node. It is often seen in response to physical activity or stress.
2. Atrial fibrillation: This is a type of arrhythmia where the heart's upper chambers (atria) contract irregularly and rapidly, leading to a rapid heart rate.
3. Ventricular tachycardia: This is a type of arrhythmia where the heart's lower chambers (ventricles) contract rapidly, often with a rate above 100 bpm.
4. Premature ventricular contractions (PVCs): These are early or extra beats that originate in the ventricles, causing a rapid heart rate.

Tachycardia can cause a range of symptoms, including palpitations, shortness of breath, chest pain, and dizziness. In severe cases, it can lead to cardiac arrhythmias, heart failure, and even death.

Diagnosis of tachycardia typically involves a physical examination, electrocardiogram (ECG), and other tests such as stress tests or echocardiography. Treatment options vary depending on the underlying cause, but may include medications to regulate the heart rate, cardioversion to restore a normal heart rhythm, or in severe cases, implantation of a pacemaker or defibrillator.

There are several possible causes of dizziness, including:

1. Inner ear problems: The inner ear is responsible for balance and equilibrium. Any disruption in the inner ear can cause dizziness.
2. Benign paroxysmal positional vertigo (BPPV): This is a condition that causes brief episodes of vertigo triggered by changes in head position.
3. Labyrinthitis: This is an inner ear infection that causes dizziness and hearing loss.
4. Vestibular migraine: This is a type of migraine that causes dizziness and other symptoms such as headaches.
5. Meniere's disease: This is a disorder of the inner ear that causes dizziness, tinnitus (ringing in the ears), and hearing loss.
6. Medication side effects: Certain medications can cause dizziness as a side effect.
7. Low blood pressure: A sudden drop in blood pressure can cause dizziness.
8. Anxiety: Anxiety can cause dizziness and other symptoms such as rapid heartbeat and shortness of breath.
9. Heart problems: Certain heart conditions such as arrhythmias or heart failure can cause dizziness.
10. Dehydration: Dehydration can cause dizziness, especially if it is severe.

If you are experiencing dizziness, it is important to seek medical attention to determine the underlying cause and receive appropriate treatment. Your healthcare provider may perform a physical examination, take a detailed medical history, and order diagnostic tests such as a hearing assessment or imaging studies to help identify the cause of your dizziness. Treatment will depend on the underlying cause, but may include medications, vestibular rehabilitation therapy, or lifestyle changes.

There are two types of hypertension:

1. Primary Hypertension: This type of hypertension has no identifiable cause and is also known as essential hypertension. It accounts for about 90% of all cases of hypertension.
2. Secondary Hypertension: This type of hypertension is caused by an underlying medical condition or medication. It accounts for about 10% of all cases of hypertension.

Some common causes of secondary hypertension include:

* Kidney disease
* Adrenal gland disorders
* Hormonal imbalances
* Certain medications
* Sleep apnea
* Cocaine use

There are also several risk factors for hypertension, including:

* Age (the risk increases with age)
* Family history of hypertension
* Obesity
* Lack of exercise
* High sodium intake
* Low potassium intake
* Stress

Hypertension is often asymptomatic, and it can cause damage to the blood vessels and organs over time. Some potential complications of hypertension include:

* Heart disease (e.g., heart attacks, heart failure)
* Stroke
* Kidney disease (e.g., chronic kidney disease, end-stage renal disease)
* Vision loss (e.g., retinopathy)
* Peripheral artery disease

Hypertension is typically diagnosed through blood pressure readings taken over a period of time. Treatment for hypertension may include lifestyle changes (e.g., diet, exercise, stress management), medications, or a combination of both. The goal of treatment is to reduce the risk of complications and improve quality of life.

There are many different types of ANS diseases, including:

1. Dysautonomia: a general term that refers to dysfunction of the autonomic nervous system.
2. Postural orthostatic tachycardia syndrome (POTS): a condition characterized by rapid heart rate and other symptoms that occur upon standing.
3. Neurocardiogenic syncope: a form of fainting caused by a sudden drop in blood pressure.
4. Multiple system atrophy (MSA): a progressive neurodegenerative disorder that affects the autonomic nervous system and other parts of the brain.
5. Parkinson's disease: a neurodegenerative disorder that can cause autonomic dysfunction, including constipation, urinary incontinence, and erectile dysfunction.
6. Dopamine deficiency: a condition characterized by low levels of the neurotransmitter dopamine, which can affect the ANS and other body systems.
7. Autonomic nervous system disorders associated with autoimmune diseases, such as Guillain-Barré syndrome and lupus.
8. Trauma: physical or emotional trauma can sometimes cause dysfunction of the autonomic nervous system.
9. Infections: certain infections, such as Lyme disease, can affect the autonomic nervous system.
10. Genetic mutations: some genetic mutations can affect the functioning of the autonomic nervous system.

Treatment for ANS diseases depends on the specific condition and its underlying cause. In some cases, medication may be prescribed to regulate heart rate, blood pressure, or other bodily functions. Lifestyle changes, such as regular exercise and stress management techniques, can also be helpful in managing symptoms. In severe cases, surgery may be necessary to correct anatomical abnormalities or repair damaged nerves.

1. Vagus nerve paralysis: A condition in which the vagus nerve is damaged or degenerated, leading to weakness or paralysis of the muscles involved in swallowing and breathing.
2. Vagus nerve neuritis: Inflammation of the vagus nerve, which can cause symptoms such as hoarseness, dysphagia, and pain in the throat.
3. Vagus nerve tumors: Abnormal growths on the vagus nerve that can cause a variety of symptoms, including difficulty swallowing, voice changes, and seizures.
4. Vagus nerve trauma: Damage to the vagus nerve due to injury or surgery, which can result in long-term consequences such as dysphagia and vocal cord paralysis.
5. Vagus nerve syndromes: A group of disorders that affect the vagus nerve and its connections with other organs, such as the heart and lungs. These syndromes can cause a range of symptoms, including seizures, difficulty breathing, and abnormal heart rhythms.

These are some examples of Vagus Nerve Diseases that can affect the quality of life of an individual. It is important to be aware of these conditions and seek medical attention if symptoms persist or worsen over time.

In other words, pure autonomic failure refers to a situation where an individual experiences a decline in their autonomic nervous system's ability to regulate involuntary functions, such as heart rate, blood pressure, digestion, and body temperature, without any identifiable underlying cause. This can result in a range of symptoms, including fatigue, dizziness, lightheadedness, and difficulty maintaining balance.

Pure autonomic failure is rare and often presents challenges for diagnosis and treatment. It may be associated with other medical conditions, such as autoimmune disorders or neurodegenerative diseases, but in some cases, the cause remains unknown. Treatment options are limited and may include medication, lifestyle modifications, and management of symptoms.

The exact cause of vasovagal syncope is not fully understood, but it is thought to be related to an imbalance in the autonomic nervous system (which controls involuntary functions such as heart rate and blood pressure). It can be triggered by a variety of factors, including:

* Strong emotions such as fear or anxiety
* Pain or discomfort
* Intense physical activity
* Dehydration or low blood sugar
* Certain medications

During a vasovagal syncope episode, the person may experience symptoms such as:

* Dizziness or lightheadedness
* Blurred vision
* Nausea or vomiting
* Sweating
* Feeling of impending doom or loss of control
* Eventually, fainting or falling to the ground

Diagnosis of vasovagal syncope is typically made based on a combination of symptoms and physical examination findings. Tests such as an electrocardiogram (ECG) or blood tests may be ordered to rule out other conditions that may be causing the symptoms. Treatment for vasovagal syncope usually involves addressing any underlying triggers, such as managing stress or avoiding certain stimuli that may cause the episodes. In some cases, medications such as beta blockers or antidepressants may be prescribed to help regulate the heart rate and blood pressure.

There are several causes of hypotension, including:

1. Dehydration: Loss of fluids and electrolytes can cause a drop in blood pressure.
2. Blood loss: Losing too much blood can lead to hypotension.
3. Medications: Certain medications, such as diuretics and beta-blockers, can lower blood pressure.
4. Heart conditions: Heart failure, cardiac tamponade, and arrhythmias can all cause hypotension.
5. Endocrine disorders: Hypothyroidism (underactive thyroid) and adrenal insufficiency can cause low blood pressure.
6. Vasodilation: A condition where the blood vessels are dilated, leading to low blood pressure.
7. Sepsis: Severe infection can cause hypotension.

Symptoms of hypotension can include:

1. Dizziness and lightheadedness
2. Fainting or passing out
3. Weakness and fatigue
4. Confusion and disorientation
5. Pale, cool, or clammy skin
6. Fast or weak pulse
7. Shortness of breath
8. Nausea and vomiting

If you suspect that you or someone else is experiencing hypotension, it is important to seek medical attention immediately. Treatment will depend on the underlying cause of the condition, but may include fluids, electrolytes, and medication to raise blood pressure. In severe cases, hospitalization may be necessary.

The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure causes the heart rate to decrease. ... The baroreflex can be used to treat resistant hypertension. This stimulation is provided by a pacemaker-like device. While the ... The baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms that helps to maintain blood pressure at ... The ability of baroreflex activation therapy to reduce sympathetic nerve activity suggests a potential in the treatment of ...
... is an approach to treating high blood pressure and the symptoms of heart failure. It uses an ... Baroreflex activation therapy is used to reduce the symptoms of heart failure in patients who do not qualify for cardiac ... Baroreflex activation is distinct from vagal stimulation. Electrical stimulation of the external surfaces of the carotid sinus ... Gordin, D; Vikatmaa, P; Vikatmaa, L; Groop, PH; Albäck, A; Tikkanen, I (2016). "Baroreflex activation therapy in the treatment ...
Baroreflex failure: In the human body, baroreflexes maintain blood pressure homeostasis. Typically, the three circumstances ... Reduced arterial compliance and baroreflex failure may contribute to trigger a response as well. Diagnosis is typically by 24 ... "Baroreflex Failure". Hypertension. 45 (5): 834-839. doi:10.1161/01.HYP.0000160355.93303.72. PMID 15837841. Farsalinos, ... that baroreflexes can fail are: problems with the central processing, damage to the Autonomic Nervous System which is ...
Gropper, Michael A. "Baroreflex". Science Direct. "The Arterial Supply to the Central Nervous System". Teach me Anatomy. ... Due to the baroreflex, this inhibits sympathetic vasomotor and cardiac stimulation and increases parasympathetic stimulation of ...
HRT is widely considered[by whom?] to be a baroreflex phenomenon. That is, a PVC interrupts the normal cardiac cycle, so the ... and activate the baroreflex in reverse. This time, the brain reinstates parasympathetic nerve signals and decreases sympathetic ...
Baroreflex Carotid body S., Pellerito, John; F., Polak, Joseph (2012). Introduction to vascular ultrasonography. Saunders/ ... Stimulation of baroreceptors at the carotid sinus can be used to treat resistant hypertension via activation of the baroreflex ... Physical assault at this point, producing massive baroreflex activation can cause dramatic falls in blood pressure and cerebral ... This can be used therapeutically in treatment of resistant hypertension by baroreflex activation. ...
The RVLM is notably involved in the baroreflex. It receives inhibitory GABAergic input from the caudal ventrolateral medulla ( ...
"Neuroprosthetic baroreflex controls haemodynamics after spinal cord injury". Nature. 590 (7845): 308-314. doi:10.1038/s41586- ...
Masuki S, Takeoka M, Taniguchi S, Nose H (March 2003). "Enhanced baroreflex sensitivity in free-moving calponin knockout mice ...
It is widely accepted that the Cushing reflex acts as a baroreflex, or homeostatic mechanism for the maintenance of blood ... Schmidt EA, Czosnyka Z, Momjian S, Czosnyka M, Bech RA, Pickard JD (2005). "Intracranial baroreflex yielding an early cushing ...
Because the baroreflex is controlled through brain stem mechanisms that communicate directly with the insula and amygdala, ... When blood pressure goes up, the baroreflex makes heart rate go down. The opposite happens when blood pressure goes down. ... The most direct effect of HRV biofeedback is on the baroreflex, a homeostatic reflex that helps control blood pressure ... Thus HRV biofeedback exercises the baroreflex, and strengthens it. This apparently has the effect of modulating autonomic ...
This baroreflex resetting seems to be mediated, at least partly, by a central action of angiotensin II. Additional small- ... Guo GB, Abboud FM (May 1984). "Impaired central mediation of the arterial baroreflex in chronic renal hypertension". The ... Resistant hypertension can be treated by electrically stimulating the baroreflex with a pacemaker-like device. Another system ... Guo GB, Thames MD, Abboud FM (August 1983). "Arterial baroreflexes in renal hypertensive rabbits. Selectivity and redundancy of ...
The body continually attempts to maintain homeostasis through the baroreflex. This balance in the autonomic neural input to the ...
2005). "Impaired Baroreflex Gain in Patients with Inappropriate Sinus Tachycardia". Journal of Cardiovascular Electrophysiology ...
"Reduced heart rate variability and baroreflex sensitivity in primary biliary cirrhosis. Hollingsworth, K.G.; Newton, J.L.; ...
Gribbin, B; Pickering, TG; Sleight, P; Peto, R (October 1971). "Effect of age and high blood pressure on baroreflex sensitivity ...
"Spectral analysis of the blood pressure signal, heart rate and baroreflex control". School of Medicine. University of Buenos ...
Sun, MK; Reis, DJ (1992). "Effects of systemic ethanol on medullary vasomotor neurons and baroreflexes". Neuroscience Letters. ...
"The BK channel beta1 subunit gene is associated with human baroreflex and blood pressure regulation". Journal of Hypertension. ...
"Baroreflex effectiveness index: an additional measure of baroreflex control of heart rate in daily life". American Journal of ... and technologies for continuous monitoring and processing of BP and HR signals in order to investigate the baroreflex control ...
The cardiopulmonary baroreflex responds to an increase in CVP by decreasing systemic vascular resistance while increasing heart ... "Stimulation of the Cardiopulmonary Baroreflex Enhances Ventricular Contractility in Awake Dogs: A Mathematical Analysis Study ...
June 2004). "Acute arterio-venous fistula occlusion decreases sympathetic activity and improves baroreflex control in kidney ...
The baroreflex response for maintaining cardiovascular stability is suppressed in the patients who received the ETS. Exertional ... Kawamata YT, Homma E, Kawamata T, Omote K, Namiki A (2001). "Influence of Endoscopic Thoracic Sympathectomy on Baroreflex ... baroreflex, lung volume, pupil dilation, skin temperature and other aspects of the autonomic nervous system, like the essential ... veins Sympathetic denervation is one of the causes of Mönckeberg's sclerosis T2-3 sympathectomy suppressed baroreflex control ...
Some biological systems exhibit negative feedback such as the baroreflex in blood pressure regulation and erythropoiesis. Many ...
Baroreflex and autonomic pathways normally ensure that blood pressure is maintained despite various stimuli, including postural ... largely may be due to an activation of the renin system caused by nephroptosis and partly due to a reduced baroreflex ...
2006). "Short-term electroacupuncture at Zusanli resets the arterial baroreflex neural arc toward lower sympathetic nerve ...
It also impairs baroreflex control (which helps to control blood pressure) and cardiac autonomic functioning (which has many ... Al-Kubati, M; Al-Kubati, AS; al'Absi, M; Fiser, B. (2006). "The short-term effect of water-pipe smoking on the baroreflex ...
"Effect of Tai Chi Training on Baroreflex Sensitivity and Heart Rate Variability in Patients With Coronary Heart Disease". ...
The findings support earlier observations that weightlessness results in a decrease of MSNA activity through a baroreflex ... Instantaneous sympathetic activity in muscle nerves (MSA / MSNA) is heavily controlled by baroreflex mechanisms, resulting in a ...
The resultant lowering of blood pressure is sensed by carotid sinus baroreceptors, and stimulates the baroreflex to inhibit ... interplay among the baroreflex, the cardiopulmonary reflexes and the chemoreflex". Brazilian Journal of Medical and Biological ... The sites of the chemoreflex and baroreflex input overlap and there is evidence that these reflexes modify each other, probably ...
Assessment of cardiac baroreflex sensitivity may help identify patients with treatment-resistant hypertension who are most ... and colleagues showed that impaired cardiac baroreflex ...
Portal de Revistas Académicas Chilenas proporciona acceso abierto a las publicaciones editadas por universidades, sociedades científicas, organismos gubernamentales y ONGs editadas e Chile
These risks and potential risks of chronic device based baroreflex activation may include, but are not limited to: stroke, ... Stay up-to-date on the latest news, insights and best practices on Barostim Baroreflex Activation Therapy. ... baroreflex failure or autonomic neuropathy, uncontrolled symptomatic cardiac bradyarrhythmias, carotid atherosclerosis that is ...
Interestingly though, baroreflex performance appeared better maintained in e-CEA than in s-CEA. This may be related to the ... Interestingly though, baroreflex performance appeared better maintained in e-CEA than in s-CEA. This may be related to the ... Notably, baroreflex function was better maintained in e-CEA, compared to standard CEA. (BRS at rest: young controls 19.93 ± ... Notably, baroreflex function was better maintained in e-CEA, compared to standard CEA. (BRS at rest: young controls 19.93 ± ...
Arterial (aortic+carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of ... Arterial (aortic+carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of ... Arterial (aortic+carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of ... Arterial (aortic+carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of ...
Altered baroreflex function is well documented in hypertension; however, the female sex remains far less studied compared with ... Functional symmetry of the aortic baroreflex in female spontaneously hypertensive rats. Salman, Ibrahim M. Afiliação *Salman IM ... We have previously demonstrated a left-sided dominance in the expression of aortic baroreflex function in male spontaneously ... This study, therefore, assessed the contribution of left and right aortic baroreceptor afferents to baroreflex modulation in ...
Comparison of aortic and carotid baroreflex stimulus-response characteristics in humans. Scott A. Smith, Ross G. Querry, Paul J ... Arterial (aortic+carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of ... Comparison of aortic and carotid baroreflex stimulus-response characteristics in humans. / Smith, Scott A.; Querry, Ross G.; ... Arterial (aortic+carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of ...
T1 - Enhanced pressor responsiveness to central cholinergic activation by physostigmine and impaired baroreflex function in ... title = "Enhanced pressor responsiveness to central cholinergic activation by physostigmine and impaired baroreflex function in ... Enhanced pressor responsiveness to central cholinergic activation by physostigmine and impaired baroreflex function in ... Enhanced pressor responsiveness to central cholinergic activation by physostigmine and impaired baroreflex function in ...
Lai, CJ, Yang, CCH, Hsu, YY, Lin, YN & Kuo, TBJ 2006, Enhanced sympathetic outflow and decreased baroreflex sensitivity are ... Dive into the research topics of Enhanced sympathetic outflow and decreased baroreflex sensitivity are associated with ... Enhanced sympathetic outflow and decreased baroreflex sensitivity are associated with intermittent hypoxia-induced systemic ... Enhanced sympathetic outflow and decreased baroreflex sensitivity are associated with intermittent hypoxia-induced systemic ...
... central baroreflexes; ABR, arterial baroreflex; Metabo, metaboreflex; Symp-Adr, sympatho-adrenal; Thermo, thermoregulatory ... Spontaneous baroreflex measures are unable to detect age-related impairments in cardiac baroreflex function during dynamic ... 2006). Frequency-dependent baroreflex control of blood pressure and heart rate during physical exercise. Int. J. Cardiol. 107, ... Raven, P. B., Fadel, P. J., and Ogoh, S. (2006). Arterial baroreflex resetting during exercise: a current perspective. Exp. ...
Because the effects of promethazine on autonomic cardiovascular mechanisms in general and baroreflex function in particular ... The 0.05 to 0.15 Hz range was chosen to encompass R-R interval frequencies that are considered to reflect baroreflex related ... carotid baroreflex function, and venous plasma catecholamine levels. ...
Baroreflex Failure (Genetic and Rare Diseases Information Center) * Congenital Central Hypoventilation Syndrome (Genetic and ...
ACE inhibition did not change the spontaneous baroreflex indices (gain and baroreflex effectiveness index) in ELA-2 KO mice. ... Spontaneous baroreflex was assessed by the sequencing method. ACE inhibition caused a significant decrease in mean arterial ...
Baroreflex. Clonidine. Hypotension. Munchausen Syndrome. Behcet Syndrome. Hypotension, Orthostatic. Pain. To see the data from ...
Carotid baroreflex activation therapy for resistant hypertension. Nat Rev Cardiol. 2015 Aug. 12(8):451-63. [QxMD MEDLINE Link] ... Chunbin W, Fu S, Jing H. Efficacy and safety of baroreflex activation therapy for treatment of resistant hypertension: a ...
... Baroreflex Activation in No-CRT HF Scores Again, FDA Watching Medscape Medical News, May 17, 2019 ...
Karemaker, J.M. (2009). Counterpoint: Respiratory sinus arrhythmia is due to the baroreflex mechanism. Journal of Applied ... 2003). Heart rate variability biofeedback increases baroreflex gain and peak expiratory flow. Psychosomatic Medicine, 65(5), ... Counterpoint: Respiratory sinus arrhythmia is due to the baroreflex mechanism. . Journal of Applied Physiology,. 106. (. 5. ), ... Heart rate variability biofeedback increases baroreflex gain and peak expiratory flow. . Psychosomatic Medicine,. 65. (. 5. ), ...
Journal Article 2014; 35(2): 142-148 PubMed PMID: 24878978 Citation Keywords: Adult, Baroreflex:physiology, Cardiovascular ... autonomic activity was assessed using baroreflex sensitivity (BRS).. RESULTS: We enrolled 31 patients (42.1±11.7 years) with ...
The most pronounced synchronization of the LF parameter, which reflects baroreflex activity, with variations in the GMF was ... Differences in the Sensitivity of the Baroreflex of Heart Rate Regulation to Local Geomagnetic Field Variations in Normotensive ... of the LF parameter with variations in the GMF components indicates a decrease in the sensitivity of the baroreflex mechanism ...
Sugar-sweetened soft drink consumption acutely decreases spontaneous baroreflex sensitivity and heart rate variability. ... and decreases spontaneous cardiovagal baroreflex sensitivity (cBRS) and heart rate variability (HRV). However, if consuming ...
... increases in baroreflex sensitivity, relaxation, and nitric oxide bioavailability seem to play important roles.8 ...
The cardiovascular profile of a microgravity-exposed individual is marked by a 15-20% hypovolemia, altered baroreflex and ...
Restoration of suppressed baroreflex sensitivity in rats with hereditary diabetes insipidus (Brattleboro rats) by arginine- ... Restoration of suppressed baroreflex sensitivity in rats with hereditary diabetes insipidus (Brattleboro rats) by arginine- ...
Vasoconstriction Response to Mental Stress in Sickle Cell Disease: The Role of the Cardiac and Vascular Baroreflexes Front ...
Tools for EEG, EMG, ECG, HRV, RSA, ECG Lead II, respiration, blood pressure, cardiac output, baroreflex sensitivity, sleep ... baroreflex sensitivity, and actigraphy analysis, sleep staging, actigraphy, and seizure detection. ...
Baroreflex failure. This is a medical condition referring to the cardiovascular problems; that result from the damages and ... disruption of the afferent limb of the baroreflex. Its symptoms are acute or fluctuating hypertension, excessive sweating and a ...
Massage of the carotid sinus demonstrated the presence of a carotid sinus syndrome (CSS), an abnormal baroreflex response of ...
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  • From the analysis of these parameters the software provides the estimates of spontaneous baroreflex sensitivity (BRS). (unibo.it)
  • The mean arterial pressure (MAP) and interpulse interval (PPI) signals were then used to assess the autonomic functions and spontaneous baroreflex sensitivity by auto- and cross-spectral analysis, respectively. (tmu.edu.tw)
  • Sugar-sweetened soft drink consumption acutely decreases spontaneous baroreflex sensitivity and heart rate variability. (cdc.gov)
  • Functional symmetry of the aortic baroreflex in female spontaneously hypertensive rats. (bvsalud.org)
  • We have previously demonstrated a left-sided dominance in the expression of aortic baroreflex function in male spontaneously hypertensive rats (SHRs) and normotensive rats of either sex . (bvsalud.org)
  • If lateralization in aortic baroreflex function extends to hypertensive female rats remains undetermined. (bvsalud.org)
  • These data show that female SHRs, unlike male SHRs, express similar central integration of left versus right aortic baroreceptor afferent input and thus show no laterization in the aortic baroreflex during hypertension . (bvsalud.org)
  • To assess aortic-cardiac responses, neck pressure (NP) and suction (NS) were applied during PE and SN administration, respectively, to counter alterations in CSP thereby isolating the aortic baroreflex. (unthsc.edu)
  • In addition, this investigation describes a model of aortic baroreflex function in normal healthy humans, which may prove useful in identifying the origin of baroreflex dysfunction in disease- and training-induced conditions. (unthsc.edu)
  • The results of this study indicate that chronic IH-induced hypertension is associated with a facilitation of cardiovascular sympathetic outflow and inhibition of baroreflex sensitivity in conscious rats. (tmu.edu.tw)
  • In healthy humans, fructose-sweetened water consumption increases blood pressure variability (BPV) and decreases spontaneous cardiovagal baroreflex sensitivity (cBRS) and heart rate variability (HRV). (cdc.gov)
  • increases in baroreflex sensitivity, relaxation, and nitric oxide bioavailability seem to play important roles. (ifm.org)
  • Patients are contraindicated if they have been assessed to have bilateral carotid bifurcations located above the level of the mandible, baroreflex failure or autonomic neuropathy, uncontrolled symptomatic cardiac bradyarrhythmias, carotid atherosclerosis that is determined by ultrasound or angiographic evaluation greater than 50%, ulcerative plaques in the carotid artery as determined by ultrasound or angiographic evaluation, known allergy to silicone or titanium. (cvrx.com)
  • In order to characterize the stimulus-response relationships of the arterial, aortic, and carotid baroreflexes in mediating cardiac chronotropic function, we measured heart rate (HR) responses elicited by acute changes in mean arterial pressure (MAP) and carotid sinus pressure (CSP) in 11 healthy individuals. (unthsc.edu)
  • Graded levels of NP and NS were delivered to the carotid sinus using a customized neck collar device to assess the carotid-cardiac baroreflex, independent of drug infusion. (unthsc.edu)
  • Vasoconstriction Response to Mental Stress in Sickle Cell Disease: The Role of the Cardiac and Vascular Baroreflexes Front Physiol. (usc.edu)
  • Arterial (aortic+carotid) baroreflex control of HR was quantified using ramped changes in MAP induced by bolus injection of phenylephrine (PE) and sodium nitroprusside (SN). (unthsc.edu)
  • We found no significant effect of promethazine on resting mean R-R interval, arterial pressure, R-R interval power spectra, carotid baroreflex function, and venous plasma catecholamine levels. (aspetjournals.org)
  • Kawashima, K, Miwa, Y & Fujimoto, K 1988, ' Enhanced pressor responsiveness to central cholinergic activation by physostigmine and impaired baroreflex function in spontaneously hypertensive rats ', Therapeutic Research , vol. 9, no. 2, pp. 144-153. (elsevier.com)
  • Because the effects of promethazine on autonomic cardiovascular mechanisms in general and baroreflex function in particular were not known, we were unable to exclude a possible influence of promethazine on our results. (aspetjournals.org)
  • Marrocco Trischitta, Massimiliano Maria (2008) Longterm peripheral baroreflex and chemoreflex function after bilateral eversion carotid endarterectomy , [Dissertation thesis], Alma Mater Studiorum Università di Bologna. (unibo.it)
  • The aim of this study is to assess the long-term effect of the e-CEA on arterial baroreflex and peripheral chemoreflex function in humans. (unibo.it)
  • ACE inhibition did not change the spontaneous baroreflex indices (gain and baroreflex effectiveness index) in ELA-2 KO mice. (nih.gov)
  • Stay up-to-date on the latest news, insights and best practices on Barostim Baroreflex Activation Therapy. (cvrx.com)
  • Baroreflex mechanisms in major depressions. (bvsalud.org)
  • Notably, baroreflex function was better maintained in e-CEA, compared to standard CEA. (unibo.it)
  • Massage of the carotid sinus demonstrated the presence of a carotid sinus syndrome (CSS), an abnormal baroreflex response of the carotid sinus that leads to asystole and extreme hypotension. (minervamedica.it)
  • This finding indicates each baroreflex functions as both an important anti-hypotensive and anti-hypertensive mechanism. (unthsc.edu)
  • Spontaneous baroreflex was assessed by the sequencing method. (nih.gov)
  • Adekunle and Akintomide: Exercise treadmill test in type 2 diabetes mellitus patients étaient en sous-groupe de risque duc modéré et il n'y n'avait aucune différence statistiquement significative entre les mâles et les femelles à cet égard. (who.int)
  • The prospective, nonrandomized, feasibility DEBuT-HT (Device Based Therapy in Hypertension trial) study showed that, in patients with resistant hypertension (systolic BP [SBP] ≥160 mmHg or diastolic ≥90 mmHg despite ≥3 antihypertensive medications), BAT therapy using the Rheos® Baroreflex Hypertension Therapy™ (CVRx, Inc.) reduced mean BP by 21/12 mmHg after 3 months of therapy with a favorable safety profile. (medscape.com)
  • Baroreflex activation therapy (BAT) is a device-based approach that consists of an implanted pulse generator (implanted in the pectoral region), external programming system, and leads placed adjacent to the carotid sinus to deliver electrical pulses to the carotid baroreceptors. (medscape.com)
  • Because the baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure. (bvsalud.org)
  • Identifying physiological origins of baroreflex dysfunction in salt-sensitive hypertension in the Dahl SS rat.Physiol. (nih.gov)
  • Baroreflex failure is a rare disorder that causes fluctuations in blood pressure with episodes of severe hypertension (high blood pressure) and elevated heart rate in response to stress, exercise, and pain. (nih.gov)
  • Symptoms of Baroreflex failure may include headache, sweating, and a heart rate that does not respond to medications. (nih.gov)
  • In many cases, the cause of Baroreflex failure is not known. (nih.gov)
  • TI - Post-exercise depression of baroreflex slowing of the heart in humans. (nih.gov)
  • Baroreflex responses were analyzed in anesthetized STZ-AD rats using femoral catheterization for blood pressure and heart rate, and autonomic activity was assessed using specific blockers and splanchnic sympathetic nerve recordings. (nih.gov)
  • Baroreflex function in STZ-AD showed a blunted heart rate (HR) response to low blood pressure challenges, and the maximal sympathetic nerve activity was reduced. (nih.gov)
  • This is a phenomenological ODE model of baroreflex open-loop control of heart rate. (nih.gov)
  • [ 5 ] Electrical stimulation of the carotid baroreceptors results in activation of the baroreflex system with subsequent increase in the parasympathetic outflow and inhibition of the sympathetic activity. (medscape.com)