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Results for “PRESSORECEPTORS”

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At least 19 recordsLinked to original sources
PubMed1987

Pressoreceptor modulation of renal but not splenic sympathetic reflexes.

Influences of sinoaortic and vagally innervated vascular pressoreceptors on excitatory splenic and renal sympathetic responses to splenic receptor stimulation were investigated in anesthetized cats. These experiments demonstrated that these pressoreceptors have little apparent effect on the magnitude of splenic nerve responses to splenic receptor stimulation by capsaicin, bradykinin, or congestion. In contrast, activation of these pressoreceptors attenuated renal nerve responses to splenic receptor stimulation. Influences of sinoaortic and vagally innervated receptors on tonic sympathetic nerve activity also were evaluated. Stimulation of these receptors by small increases in arterial pressure (15-21 mmHg) caused equivalent inhibition of splenic and renal nerve activity; large increases (50-66 mmHg) caused significantly greater inhibition of renal than splenic nerve activity. These results illustrate that excitatory renal and splenic sympathetic responses to splenic receptor stimulation are not suppressed equally by pressoreceptor activation, vascular pressoreceptors can have greater inhibitory influences on tonic renal than splenic nerve activity, and vascular pressoreceptor influences on sympathetic reflexes are similar to those on tonic nerve activity.

Animals↗
PubMed1975

Effects of pressoreceptor stimulation on micturition relfex and urethral pressure profile in rabbits.

The influence of pressoreceptor stimulation on the micturition reflex and urethral pressure profile was studied. Stimulation of pressoreceptors of the aortic arch and carotid sinus causes an increase of parasympathetic tone and a decrease of sympathetic tone. Striated muscular tone was also decreased. Pressoreceptor stimulation was simulated by electrical stimulation of the depressor nerve in the rabbit. Our studies show that with pressoreceptor stimulation micturition occurred with 24 per cent less bladder filling and 32 per cent less intravesical pressure than before stimulation, and urethral pressure profile showed a 17 per cent decrease of the maximum and mean urethral pressure. The interpretation of the action of parasympathicomimetic and sympathicomimetic drugs on bladder and bladder neck must take into consideration the cardiovascular effects of these drugs and therefore the effect on the pressoreceptors.

Animals↗
PubMed1977

Analysis of bladder configuration and pressure from pressoreceptor stimulation in rabbits.

In a previous study (Bödeker, J., Vogt, W., Kölln, C.-P., and Nagel, R.: Invest. Urol., 12: 461, 1975.) pressoreceptor stimulation induced micturition at less than normal bladder filling. Furthermore, urethral pressure profile decreased in both maximal and mean values. In the present investigation the effects of pressoreceptor stimulation on bladder configuration, intravesical pressure, and vesicoureteral reflux were studied. With pressoreceptor stimulation, the bladder outlet became more funnel-shaped; the change in bladder configuration occurred without alteration in intravesical pressure; and vesicoureteral reflux could not be demonstrated.

Animals↗
PubMedDate not supplied

Effect of carotid pressoreceptor stimulation on integrated systemic venous bed.

In 9 mongrel dogs, venous return was completely drained from the caval veins to an oxygenator and returned to the femoral arteries with a roller pump. Perfusion rate of systemic circulation and blood pressures in both caval veins were kept constant. Changes in the oxygenator weight were recorded and reflected reciprocal changes in integrated systemic venous blood volume. The vagal nerves were dissected. The carotid sinuses were separately perfused with blood by means of a pump. In 25 experiments, increases in carotid sinus pressure of 15 to 74 mm Hg resulted in decreases in systemic arterial pressure of 10 to 57 mm Hg and increases in systemic venous blood volume of 1.1 to 4.7 ml/kg. On an average, systemic venous blood volume was changed by 1.25 +/- 0.08 ml/kg when the change in systemic arterial pressure was 10 mm Hg. It is concluded that the carotid sinus pressoreceptor reflex considerably alters the systemic venous capacity which in tern alters venous return and cardiac output. These changes in cardiac output are expected to be small, but sufficient to alter the arterial pressure considerably. Thus, they might contribute nearly as much as the reflex effect on total peripheral resistance to the reflex control of arterial pressure.

Animals↗
PubMed1976

Cardiac pressoreceptors and peripheral resistance.

The results obtained show that the pressoreceptors, probably ubicated in the left ventricle of the rat, respond to the distention with vasodilatation. The afferent tract of this reflex is in the vagus nerve and the efferent one is in the sympathetic nervous system. The probable function of this reflex is discussed.

Animals↗
PubMed1977

Afferent discharges from venous pressoreceptors in liver.

Afterent discharges were observed in dissected filaments or single nerve fibers of hepatic nerve in the guinea pig and the rabbit. Increasing the perfusion pressure of the portal vein in isolated liver preparation in the guinea pig caused an increase in afferent discharge rate. Discharge patterns were compatible with those of the slowly adapting type. Increasing the portal venous pressure by means of intravenous injection of Locke's solution into the left jugular vein in the rabbit in vivo caused an increase in afferent discharge rate. Increasing the hepatic arterial pressure was without effect. It is suggested that pressoreceptors are present in or near the venous wall of the portal venous system and that they send information about blood pressure in the portal vein to the central nervous system.

Action Potentials↗
PubMed1987

Evidence that periodontal pressoreceptors provide positive feedback to jaw closing muscles during mastication.

1. Mastication was produced by stimulation of the right motor-sensory cortex of urethan-anesthetized rabbits with 15-s trains of shocks (1-ms duration) at 50 Hz. Movements of the lower jaw and jaw muscle electromyograms (EMGs) were recorded on magnetic tape for later computer analysis. 2. The stimulus site was chosen, and stimulus intensity adjusted, so that stereotyped movements were produced that included a wide swing of the mandible to the left side during jaw closure. 3. Control trials were alternated with trials in which a steel ball (2 mm diam) was thrust between the anterior molar teeth on the left side and left in place for several seconds. 4. When the obstruction was first introduced, a jaw opening reflex was sometimes evoked if the ball struck the buccal surface of the advancing mandibular molar teeth. Thereafter, when the ball was crushed between the occlusal surfaces of the teeth, no jaw opening reflex was seen. 5. Instead, the amplitude and duration of all the jaw closing EMGs increased, beginning at least 12 ms after contact with the ball. This caused a prolongation of the slow closing (SC) phase of the cycle that, coupled with a delay in the start of activity in the digastric muscle (jaw opener), prolonged the cycle by more than 60 ms. 6. During the SC phase of the obstructed trials, the medially directed grinding stroke was exaggerated because of an increase in the contraction of the contralateral zygomaticomandibular and anterior temporal muscles. 7. After collecting data, the sensory nerves to the maxillary and mandibular anterior molar teeth were cut to eliminate feedback from the periodontal pressoreceptors. Control and obstructed trials were repeated. 8. Following denervation, the obstructed cycles were of shorter duration. The mandible still moved to the right during SC in some animals, but the increase in closer muscle EMG activity was much reduced. 9. We conclude that periodontal receptors provide positive feedback to the jaw closing muscles during mastication. This is supplemented by input from other receptors, probably muscle spindles. In addition, an increase in periodontal feedback prolongs the SC phase and the early phases of the opening stroke.

Animals↗
PubMed1976

Electron microscopic studies of the pressoreceptor fields of the carotid sinus of the dog.

In the dog, pressosensitive endings of the sinus nerve extend along the border between the adventitia and media of the carotid sinus wall. The axon endings, containing a great number of mitochondria, can be divided into small (600-2,000 nm) and large (6,000-8,000 nm) end swellings. In the terminal region the pressosensitive fibers are surrounded by ramified and highly structured Schwann "terminal cells". The topographic location in relation to elastic and collagenous tissue indicates a functional connection between receptors and efferent nerve endings in the immediate surroundings has been discussed in this report. Several axon endings contain variable amounts of glycogen which is regarded as an indication for the inactive metabolic state of the ending. Axonal swellings demonstrate considerable modification in structure, such as loss of structural integrity in mitochondria, the formation of lamellar fields, vesicular irregularities and disintegration of axoplasm, all of which are considered as the morphological expression of "wearing out", degeneration and possibly regeneration.

Animals↗