Afferent impulses in the carotid sinus nerve. I. The relation of the disharge from single end organs to arterial blood pressure

PROTOPLASMA ◽  
1933 ◽  
Vol 17 (1) ◽  
pp. 480-480
1997 ◽  
Vol 82 (2) ◽  
pp. 413-418 ◽  
Author(s):  
A. Bairam ◽  
P. De Grandpré ◽  
C. Dauphin ◽  
F. Marchal

Bairam, A., P. De Grandpré, C. Dauphin, and F. Marchal. Effects of caffeine on carotid sinus nerve chemosensory discharge in kittens and cats. J. Appl. Physiol. 82(2): 413–418, 1997.—Caffeine (C) decreases apneic episodes in premature infants and is thought to stimulate breathing mainly by a central mechanism. While the methylxanthines theophylline and aminophylline are known to alter the carotid chemoreceptor activity, there are little data on C. The aim of the study was to examine the effects of C on the carotid sinus nerve discharge (CSND) in developing animals. Nine kittens 17–21 days old and six adult cats that were anesthetized and artificially ventilated were studied. They received four consecutive doses of C, each of 10 mg/kg, administered at intervals of 20 min either as intravenous bolus injection (6 kittens, 3 cats) or continuous infusion (3 kittens, 3 cats). Bolus injections of C invariably induced a prompt but transient increase in the CSND from 4.1 ± 0.6 to 8.1 ± 1.0 (SE) impulses/s in kittens ( P = 0.01) and from 3.9 ± 0.1 to 7.9 to 1.0 impulses/s in cats (after the first injection). This response was associated with a significant decrease in arterial blood pressure. Continuous infusion of C did not induce any early change in either CSND or blood pressure in kittens or cats. Fifteen minutes after C injection or infusion was begun, CSND values in air, 8% O2-balance N2, or 100% O2 were not significantly different from control. Haloperidol administered at the end of the experiment in four cats and four kittens significantly increased CSND and did not suppress the early response to C injection. It is concluded that caffeine administered by bolus in the kitten induces a transient stimulation of the CSND that is associated with a decrease in the arterial blood pressure and is independent of the dopaminergic mechanisms in the carotid body. The lack of sustained effect implies the main mechanism to the ventilatory stimulation by C must be central.


1976 ◽  
Vol 230 (1) ◽  
pp. 19-24 ◽  
Author(s):  
G Mancia ◽  
JT Shepherd ◽  
DE Donald

Interactions among vascular reflexes evoked from carotid sinuses, carotid bodies, and cardiopulmonary region were examined in anesthetized, atropinized, and respired dogs with aortic nerves cut. The carotid sinuses were perfused at 220, 150, and 40-50 mmHg; the chemoreceptors were stimulated by perfusion with hypoxic hypercapnic blood. Cardiopulmonary vasomotor inhibition was interrupted by vagal cold block. Measurements were made of arterial blood pressure and of kidney and hindlimb vascular resistance. At sinus pressures less than 170-160 mmHg, cardiopulmonary vasomotor inhibition increased with increase in blood volume. At high sinus pressure, interruption of this augmented cardiopulmonary inhibition was as ineffective in changing vascular resistance as interruption of the lesser inhibition present during normovolemia. Chemoreceptor stimulation increased the response to vagal block at intermediate but not at high or low sinus pressure. The studies demonstrate the dominant role of the carotid sinus reflex when the three systems interact and the ineffectiveness of chemoreceptor stimulation when carotid or cardiopulmonary inhibition is maximal.


1984 ◽  
Vol 247 (5) ◽  
pp. R833-R836 ◽  
Author(s):  
E. Tomomatsu ◽  
J. P. Gilmore

Studies were undertaken in the cat to determine if moderate hemorrhage or volume expansion significantly altered carotid sinus and aortic baroreceptor activity. In addition, the experimental design provided the opportunity to compare gain of the two sets of receptors. A 20% blood volume expansion increased mean arterial blood pressure 5.2% and carotid sinus nerve activity 14.7%, whereas a 20% hemorrhage decreased mean arterial blood pressure 10.8% and carotid sinus nerve activity 32.3%. For the aortic baroreceptors, a 20% blood volume expansion increased mean arterial blood pressure 5.9% and nerve activity 10.5%, and a 20% hemorrhage decreased mean arterial blood pressure 8.9% and nerve activity 21.0%. The blood pressure-discharge curves for the carotid sinus and aortic baroreceptors were not different. The well-known high sensitivity of atrial receptors was also documented. We conclude that both high- and low-pressure receptors apprise the central nervous system of the status of intravascular volume and pressure.


Circulation ◽  
2002 ◽  
Vol 105 (11) ◽  
pp. 1329-1335 ◽  
Author(s):  
Arthur A.J. Smit ◽  
Henri J.L.M. Timmers ◽  
Wouter Wieling ◽  
Mariette Wagenaar ◽  
Henri A.M. Marres ◽  
...  

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