The Effect of Acute Hyhoxia and Carotid Sinus Nerve Section on Hypothalamic Blood Flow in the Rabbit

1975 ◽  
Vol 49 (3) ◽  
pp. 11P-12P ◽  
Author(s):  
R. A. F. Linton ◽  
Roxana Miller ◽  
I. R. Cameron
Keyword(s):  
Blood Flow ◽  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Nerve Section

Cerebrovascular response to hypoxia in baroreceptor- and chemoreceptor-denervated dogs

1981 ◽  
Vol 241 (5) ◽  
pp. H724-H731 ◽  
Author(s):  
R. J. Traystman ◽  
R. S. Fitzgerald
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Vascular Resistance ◽  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Nerve Section ◽  
Carotid Baroreceptor ◽  
Aortic Baroreceptors ◽  
Cerebral Vascular Resistance ◽  
Cerebral Vascular

Cerebral hemodynamic responses to arterial hypoxemia were studied in anesthetized paralyzed dogs that were or that had undergone carotid baroreceptor denervation, carotid chemoreceptor denervation, vagotomy, or both vagotomy and carotid sinus nerve section. Arterial O2 content was lowered from control (19.0 vol%) to 9.6 vol% by either decreasing arterial O2 tension [hypoxic hypoxemia (HH)] or increasing carboxyhemoglobin saturation[carbon-monoxide hypoxemia (COH)] at normal O2 tension. In intact animals (composite control values from all groups) HH and COH resulted in similar increases in cerebral blood flow (to 205 and 197% of control, respectively). Cerebral vascular resistance decreased more with COH than with HH (to 42 vs. 60% of control). The response from carotid baroreceptor-denervated animals and from vagotomized animals did not differ from that of the intact animals. After carotid chemoreceptor denervation and combined carotid sinus nerve section and vagotomy, both HH and COH increased cerebral blood flow to 194% of control (same increase as in intact animals, carotid baroreceptor-denervated animals, and vagotomized animals) and produced equal reductions in cerebral vascular resistance (to 34% of control). These data show that the carotid and aortic chemoreceptors are not necessary for the increase in cerebral blood flow provoked by hypoxemia and that this response is not modified by the carotid and aortic baroreceptors.

scholarly journals Intrarenal blood flow in carotid sinus nerve stimulation and hemorrhage in dogs

1975 ◽  
Vol 8 (3) ◽  
pp. 135-139 ◽  
Author(s):  
John C. Passmore ◽  
Howard L. Strauss ◽  
William Z. Kolozsi
Keyword(s):  
Blood Flow ◽  
Nerve Stimulation ◽  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Intrarenal Blood Flow ◽  
Carotid Sinus Nerve Stimulation

Analysis of inhibitory effect of dopamine on carotid body chemoreceptors in cats

1976 ◽  
Vol 230 (6) ◽  
pp. 1494-1498 ◽  
Author(s):  
SR Sampson ◽  
MJ Aminoff ◽  
RA Jaffe ◽  
EH Vidruk
Keyword(s):  
Blood Flow ◽  
Carotid Body ◽  
Carotid Sinus ◽  
Direct Action ◽  
Inhibitory Effect ◽  
Gas Mixture ◽  
Carotid Sinus Nerve ◽  
Perfusion Pump ◽  
Flow Through ◽  
Carotid Body Chemoreceptors

The inhibitory effect of dopamine on carotid body chemoreceptors was studied in anesthetized cats to determine whether it was dependent on changes in blood flow in the vicinity of the receptors. The blood supply to the carotid body was isolated, and flow was controlled with a perfusion pump. Single- or few-fiber recordings were made from the peripheral end of the cut carotid sinus nerve in seven cats. The rate of discharge of 68 chemoreceptor strands increased when flow through the carotid body was stopped. This response was reduced or abolished by dopamine in animals ventilated with either room air (15 strands) or a gas mixture of 95% O2 and 5% CO2 (53 strands). These results suggest that dopamine exerts its inhibitory effect primarily through a direct action on the chemoreceptors rather than by a vasomotor effect in the carotid body.

Effects of decortication and carotid sinus nerve section on ventilation of the rat

1981 ◽  
Vol 43 (3) ◽  
pp. 263-273 ◽  
Author(s):  
M. Maskrey ◽  
D. Megirian ◽  
S.C. Nicol
Keyword(s):  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Nerve Section

scholarly journals Carotid sinus nerve section and the increase in plasma cortisol during acute hypoxia in fetal sheep.

1994 ◽  
Vol 477 (1) ◽  
pp. 75-80 ◽  
Author(s):  
D A Giussani ◽  
H H McGarrigle ◽  
P J Moore ◽  
L Bennet ◽  
J A Spencer ◽  
...  
Keyword(s):  
Plasma Cortisol ◽  
Carotid Sinus ◽  
Acute Hypoxia ◽  
Carotid Sinus Nerve ◽  
Nerve Section ◽  
Fetal Sheep

Integration of chemoreceptor stimuli by rostral brainstem respiratory areas

1975 ◽  
Vol 39 (2) ◽  
pp. 209-214 ◽  
Author(s):  
W. M. Saint John ◽  
G. C. Bond ◽  
J. N. Pasley
Keyword(s):  
Tidal Volume ◽  
Respiratory Activity ◽  
Carotid Sinus ◽  
Minute Volume ◽  
Carotid Sinus Nerve ◽  
Nerve Section ◽  
Bilateral Vagotomy ◽  
Pneumotaxic Center ◽  
Decerebrate Cats ◽  
Paco2 Level

Ventilatory regulation by brainstem sites rostral to the midpontile level was assessed in decerebrate cats by comparing the effects of punctate pneumotaxic center lesions with those of midpontile transection. After either procedure, PACO2 was significantly elevated. Moreover an equal suppression of hypercapnia-induced minute volumes and maintenance, at some PACO2 levels, of minute volume responses to hypoxia was observed. Tidal volume elevations accounted for the maintenance of hypoxia-induced minute volumes. Following pneumotaxic center lesions, hypercapnia-induced tidal volumes were higher than those exhibited subsequent to midpontile transection. After carotid sinus nerve section, PACO2 was elevated and hypoxia-induced alterations were abolished. Bilateral vagotomy resulted in apneusis. These data demonstrate that, in the brainstem area examined, only the pneumotaxic center influences the PACO2 level or set point for respiratory activity. A locus of tidal volume generation is ascribed to rostral brainstem sites outside this pneumotaxic center. Data obtained support the hypothesis of a differential brainstem integration of peripheral and central chemoreceptor afferent stimuli.

Peripheral baroreceptor control of neurohypophysial blood flow during hemorrhage

1989 ◽  
Vol 257 (5) ◽  
pp. H1498-H1506
Author(s):  
L. M. Vella ◽  
D. F. Hanley ◽  
D. A. Wilson ◽  
R. J. Traystman
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Time Course ◽  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Neural Lobe ◽  
Flow Response ◽  
Bilateral Vagotomy ◽  
Multiple Levels ◽  
Plasma Arginine

We measured neurohypophysial blood flow (NHBF) in dogs made hypotensive to study the time course of neurohypophysial autoregulation. We found that the neurohypophysis has a unique autoregulatory response in which blood flow increases transiently before establishing a stable perfusion level. During the "hyperemic" phase, the time course of the flow transient correlates with an increased plasma arginine vasopressin (pAVP) neurosecretory transient. However, unlike pAVP, blood flow does not remain elevated. The transitory nature of the flow response led us to evaluate the hypothesis that peripheral baroreceptor activity may be responsible for the hyperemic phase. Bilateral vagotomy and carotid sinus nerve denervation attenuated the increase in neural lobe blood flow (NLBF) to a standardized step to 80 mmHg mean arterial pressure. The pAVP response was enhanced both by vagotomy and carotid sinus denervation. Combined denervation abolished both the pAVP and the NLBF responses. We conclude that NHBF is autoregulated; however, control may be exerted at multiple levels, i.e., via nerves as well as local metabolic mechanisms. The peripheral baroreceptors influence NHBF primarily during periods of changing blood pressure. When blood pressure is stable, local mechanisms appear to be dominant.

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