Interaction of right and left carotid sinus baroreflexes in the dog

1986 ◽  
Vol 250 (1) ◽  
pp. H96-H107 ◽  
Author(s):  
A. S. Greene ◽  
M. J. Brunner ◽  
A. A. Shoukas

Carotid sinus reflex interactions were studied in 10 dogs anesthetized with pentobarbital sodium. The right and left carotid sinus regions were isolated and perfused at controlled pressures. Pressure in the right and left carotid sinuses were independently varied, and the resulting steady-state reflex changes in arterial pressure, heart rate, respiratory frequency, tidal volume, and total ventilation were measured. Reflex changes when carotid sinus pressure was changed on one side were strongly influenced by pressure in the contralateral carotid sinus (P less than 0.05). Right carotid sinus gain was found to be 0.628 +/- 0.058 at a left carotid sinus pressure of 50 mmHg and 0.148 +/- 0.027 when left carotid sinus pressure was 200 mmHg. Similar results were found for left carotid sinus gain. Suppression was also found for heart rate, respiratory rate, tidal volume, and total ventilation. The hypothesis that rapid resetting of one carotid sinus baroreflex might influence responses from the other side was also tested. Although ipsilateral resetting was consistently observed, no contralateral component of the resetting was detected. An additional inhibitory summation between the right and left carotid sinuses was found such that simultaneous excitation of both receptors resulted in a smaller reflex response than did the sum of individual responses. Sympathetic denervation of the carotid sinus region had no effect.

1993 ◽  
Vol 264 (4) ◽  
pp. H1215-H1222 ◽  
Author(s):  
L. Hayward ◽  
M. Hay ◽  
R. B. Felder

The effect of prolonged aortic depressor nerve (ADN) stimulation on carotid sinus baroreflex regulation of arterial pressure (AP) and renal sympathetic nerve activity (RSNA) was examined in anesthetized rabbits. Ramp increases in carotid sinus pressure (CSP) were repeated before and after 5 min of bilateral ADN stimulation. One minute after ADN stimulation the curve relating AP to CSP had shifted up and to the right, characterized by significant increases (P < 0.05) in the maximum (91 +/- 2 to 101 +/- 3 mmHg; mean +/- SE), midpoint (118 +/- 7 to 125 +/- 8 mmHg CSP), and minimum (45 +/- 3 to 53 +/- 4 mmHg) of the AP reflex curve. There was a parallel shift downward of the curve relating RSNA to CSP, characterized by significant decreases in the maximum [100 +/- 0 to 66 +/- 8% of maximum control RSNA value (%max)], the range (90 +/- 2 to 59 +/- 8%max), and the gain (-1.0 +/- 0.2 to -0.5 +/- 0.1%max/mmHg) of the RSNA reflex curve. Values returned to control within 10 min of cessation of ADN stimulation. These results suggest that central neurons processing baroreflex information from one set of mechanoreceptors can be reset by convergent signals arising from another baroreceptor site.


2000 ◽  
Vol 88 (3) ◽  
pp. 957-965 ◽  
Author(s):  
Jacqui Raymond ◽  
Glen M. Davis ◽  
Martinus N. van der Plas ◽  
Herbert Groeller ◽  
Scott Simcox

This study investigated control of heart rate (HR) and mean arterial pressure (MAP) at rest and during electrical stimulation (ES) leg cycling exercise (LCE) in paraplegics (Para). Seven men with complete spinal lesions (T5–T11) and six able-bodied (AB) men participated in this study. Beat-to-beat changes in HR and MAP were recorded during carotid sinus perturbation. Carotid baroreflex function curves were derived at rest and during ES-LCE for Para and during voluntary cycling (Vol) for AB. From rest to ES-LCE, oxygen uptake (V˙o 2) increased (by 0.43 l/min) and HR rose (by 11 beats/min), yet MAP remained unchanged. In AB, Vol increased V˙o 2 (by 0.53 l/min), HR (by 22 beats/min), and MAP (by 8 mmHg). ES-LCE did not alter the carotid sinus pressure (CSP)-MAP relationship, but it displaced the CSP-HR relationship upward relative to rest. No rightward shift was observed during ES-LCE. Vol by AB produced an upward and rightward displacement of the CSP-MAP and CSP-HR relationships relative to rest. These findings suggested that the carotid sinus baroreflex was not reset during ES-LCE in Para.


1975 ◽  
Vol 38 (1) ◽  
pp. 1-4 ◽  
Author(s):  
J. DiSalvo ◽  
R. Reynolds ◽  
J. L. Robinson ◽  
G. Grupp

Effects of carotid sinus pressure on arterial pressure, atrial rate, and ventricular rate were examined in anesthetized normal dogs and in dogs with chronic complete A-V block. Change in arterial pressure per mmHg change in sinus pressure was 0.8 plus or minus 0.2 mmHg for controls but increased (P is less than 0.001) to 1.6 plus or minus 0.1 mmHg in A-V blocked dogs. Arterial pressure was 140–145 mmHg at low sinus pressure in both groups, but at high sinus pressure arterial pressure was significantly lower in A-V blocked dogs (44 plus or minus 4 mmHg) than in controls (92 plus or minus 8 mmHg). These differences were virtually abolished after vagotomy. Heart rate increased in normal dogs as sinus pressure was increased before vagotomy, but decreased after vagotomy. In blocked dogs atrial and ventricular rates decreased at high sinus pressure either before or after vagotomy. The results show that reflex circulatory responses to changes in carotid sinus pressure are enhanced in dogs with A-V block. This enhancement may involve attenuation of buffering influences exerted from other baroreceptors whose afferents are in the vagus nerves.


1991 ◽  
Vol 261 (4) ◽  
pp. R950-R956 ◽  
Author(s):  
K. E. Wehberg ◽  
G. J. Gala ◽  
M. J. Brunner

We compared carotid sinus baroreflex control of endogenous plasma arginine vasopressin (AVP) in chronically prepared conscious and acutely prepared anesthetized dogs. The carotid sinuses of both conscious and pentobarbital-anesthetized dogs were isolated bilaterally and perfused at constant pressures. Carotid sinus pressure (CSP) was changed between 200 and 50 mmHg in 25-mmHg steps in intact conscious and anesthetized dogs. Similar runs were repeated after vagotomy. Mean arterial pressure (MAP) and heart rate (HR) were monitored. At each interval of CSP, blood was withdrawn for AVP analysis by radioimmunoassay. MAP responses to changes in CSP were not different in the four experimental groups. Both anesthesia and vagotomy increased the HR responses to changes in CSP. With vagi intact, AVP increased at high CSP in conscious but not in anesthetized dogs. After vagotomy, low CSP led to an increase in plasma AVP that did not differ between conscious and anesthetized dogs. The results suggest that the release of AVP is modulated by the action of the carotid baroreflex as a normal component of an integrated efferent response. The response is similar in conscious and pentobarbital-anesthetized dogs and is normally buffered by reflexes with vagal afferents.


2017 ◽  
Vol 3 ◽  
pp. 233372141770807 ◽  
Author(s):  
Konosuke Sasaki ◽  
Mayu Haga ◽  
Sarina Bao ◽  
Haruka Sato ◽  
Yoshikatsu Saiki ◽  
...  

Objectives: The aim of this study was to evaluate the effect of the supine, left lateral decubitus, and right lateral decubitus positions on autonomic nervous activity in elderly adults by using spectral analysis of heart rate variability (HRV). Method: Forty-five adults aged 73.6 ± 5.7 years were enrolled. After lying in the supine position, all participants moved to the lateral decubitus positions in a random order and maintained the positions for 10 min, while electrocardiographic data were recorded to measure HRV. Results: The lowest heart rate continued for 10 min when participants were in the left lateral decubitus position compared with the other two positions ( p < .001), while the HRV indexes remained unchanged. The low-frequency HRV to high-frequency HRV ratio (LF/HF) for the right lateral decubitus position was significantly lower than that for the other positions. Discussion: The right lateral decubitus position may attenuate sympathetic nerve activity in elderly adults.


1998 ◽  
Vol 275 (1) ◽  
pp. H322-H329 ◽  
Author(s):  
Kelly P. McKeown ◽  
Artin A. Shoukas

We have developed a chronic technique to isolate the carotid sinus baroreceptor region in the conscious rat model. Our technique, when used in conjunction with other methods, allows for the study of the control of arterial pressure, heart rate, and cardiac output by the carotid sinus baroreceptor reflex in conscious, unrestrained rats. The performance of our technique was evaluated in two strains: normotensive Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR). Each rat was instrumented with an aortic flow probe and a catheter placed in the right femoral artery to monitor cardiac output and arterial pressure, respectively. The cervical sympathetic trunk and aortic depressor nerve were ligated and cut bilaterally, leaving vagus nerves intact. The right and left carotid sinuses were isolated using our new technique. We tested the open-loop function of the carotid sinus baroreceptor reflex system in the conscious rat after recovery from the isolation surgery. We found that changes in nonpulsatile carotid sinus pressure caused significant changes in arterial pressure, heart rate, and total peripheral resistance in both rat strains. However, the cardiac output responses differed dramatically between strains. Significant changes were seen in the cardiac output response of SHR, whereas no significant changes were observed in normotensive SD rats. We have found this technique to be a highly reliable tool for the study of the carotid sinus baroreceptor reflex system in the conscious rat.


1992 ◽  
Vol 262 (5) ◽  
pp. H1508-H1514
Author(s):  
M. J. Brunner ◽  
M. D. Kligman

The hypothesis tested was that the rapid resetting of the arterial baroreflex control of arterial pressure in normotension could be demonstrated in experimental hypertension. After the development of experimental hypertension (using a bilateral renal wrap technique), rapid resetting of arterial pressure and heart rate (HR) was acutely assessed under pentobarbital sodium anesthesia in hypertensive and normotensive vagotomized dogs. The carotid sinus area was isolated and perfused at controlled carotid sinus pressures (CSPs). Baroreflex response [mean arterial pressure (MAP) and HR] curves were measured after three carotid sinus conditioning pressures (50, 125, and 200 mmHg) were applied. For the MAP response, the CSPo (CSP at point of maximum reflex gain) increased significantly to the same extent in both groups with increasing conditioning pressures (with 22.2 and 16.7% resetting in the normotensive group, and 20.3 and 14.2% resetting in the hypertensive group). We conclude that short-term adjustments to changes in prevailing pressure (rapid resetting) occur in the arterial pressure response in experimental hypertension to the same extent seen in normotension.


1991 ◽  
Vol 260 (1) ◽  
pp. H300-H303 ◽  
Author(s):  
A. A. Shoukas ◽  
C. A. Callahan ◽  
J. M. Lash ◽  
E. B. Haase

We developed a method by which we can completely isolate the carotid sinus baroreceptor regions in the rat. The carotid sinus baroreceptor region is exposed and, with the use of extra-fine forceps, a human hair is placed around and tied at the root of the bifurcation. This procedure occludes the external carotid artery and blood flow to the carotid body. An injector is then attached to a catheter in the common carotid artery. We introduce a cylindrical rubber plug into either the palentine or internal carotid artery. A second plug is introduced to occlude the other artery. In six of the eight rats studied, these procedures completely isolated the carotid sinus region. In those cases where a small leak persisted at a carotid sinus pressure of 180 mmHg, we introduced a small particle of the animal's own previously clotted blood. Carotid sinus pressure was either randomly changed between 40 and 180 mmHg in 20-mmHg increments or in sequential 20-mmHg steps from 40 to 180 mmHg while measuring the animal's pulsatile and mean blood pressures. Arterial pressure-carotid sinus pressure relationship indicates that there is a highly sigmoidal relationship between the two pressures. The peak gain of the carotid sinus reflex system had a range from 1.5 to 4.0 and a mean value of 2.07 +/- 0.08. Our data indicate that the rat exhibits a significant carotid sinus baroreceptor reflex response. This technique combined with other techniques will allow for the study of neural control of cardiovascular function in the rat.


2021 ◽  
Vol 5 (3) ◽  
pp. 306
Author(s):  
Vicky Agnes Arundy ◽  
Iskandar Fitri ◽  
Eri Mardiani

Heart disease is a condition when the heart is experiencing a disorder. The forms of disturbance that are experienced are usually various. Usually there is a disturbance in the blood vessels of the heart, heart rate, heart cover, or congenital problems. The heart itself is a muscle consisting of four chambers. That is, the first two rooms are located at the top, the atrium (foyer) to the left and right. Then the other two rooms are at the bottom, namely the right and left ventricles. To provide information on how to diagnose the type of disease and how to control heart disease, an application of an expert system that can represent someone who is an expert in their field is needed to provide solutions to this disease problem using the Case-Based Reasoning method with the Sorensen Coeffient approach. The result of this research is the creation of an expert system for diagnosing heart disease using the Case-Based Reasoning method with the Sorensen Coeffient approach which is able to provide solutions to heart disease.Keywords:CBR, Expert system, Heart Disease, Method Sorensen Coeffient.


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