Left heart and arterial baroreceptors interact in control of plasma vasopressin, renin, and cortisol in awake dogs

1994 ◽  
Vol 266 (3) ◽  
pp. R879-R888 ◽  
Author(s):  
J. L. Andersen ◽  
L. J. Andersen ◽  
T. N. Thrasher ◽  
L. C. Keil ◽  
D. J. Ramsay

Arterial hypotension induced by constriction of the ascending aorta (AA) causes increases in left atrial pressure (LAP) and plasma atrial natriuretic peptide (ANP), but no change in plasma arginine vasopressin (AVP), plasma renin activity (PRA), or cortisol. In the present study, we tested the hypothesis that the rise in left heart pressure during constriction of the AA suppressed the stimulation of AVP, renin, and cortisol secretion in response to arterial hypotension. Dogs were prepared with inflatable cuffs around the AA, the pulmonary artery (PA), and the thoracic inferior vena cava (IVC) and with catheters in the left and right atria and abdominal aorta. In one series of experiments, the AA was constricted to lower mean arterial pressure (MAP) 10 or 20% below control for 15 min. Then, either the PA or the IVC was constricted to bring LAP back to control levels but without altering the degree of arterial hypotension. Constriction of the AA alone led to significant increases in LAP and plasma ANP but no change in plasma AVP, cortisol, or PRA. Reducing LAP to control levels by constriction of either the PA or IVC led to significant and similar increases in plasma AVP, cortisol, and PRA. Plasma ANP fell significantly 10 min after LAP was normalized by constriction of the IVC but not when LAP was normalized by constriction of the PA, because PA constriction caused a significant rise in right atrial pressure that stimulated ANP secretion. The increases in plasma AVP and PRA after normalizing LAP by constriction of the PA were compared with the increases obtained during identical falls in MAP induced by constriction of the IVC alone, a maneuver that lowers LAP below control. The increases in plasma AVP in the two conditions were identical, indicating that the stimulation of left heart baroreceptors alone can account for the suppression of AVP secretion in response to unloading arterial baroreceptors. In contrast, there was a greater rise in PRA during hypotension caused by constriction of the IVC alone compared with the condition in which LAP was normalized but plasma ANP remained elevated. This suggests that increased left heart pressure inhibits renin secretion in response to arterial hypotension by reflex mechanisms and by increased plasma ANP concentration.

1992 ◽  
Vol 263 (5) ◽  
pp. R1071-R1077 ◽  
Author(s):  
D. H. Carr ◽  
D. B. Jennings ◽  
T. N. Thrasher ◽  
L. C. Keil ◽  
D. J. Ramsay

We have reported that increased left heart pressure inhibits increases in plasma renin activity (PRA), arginine vasopressin (AVP), and cortisol during arterial hypotension. The goal of this study was to determine whether increases in right heart pressure also inhibited hormonal responses to hypotension. Seven dogs were chronically instrumented with inflatable cuffs around the ascending aorta (AA), the pulmonary artery (PA), and the thoracic inferior vena cava (IVC), as well as with catheters in both atria, the abdominal aorta, and vena cava. The IVC, the PA, and the AA cuffs were inflated on different days to cause step reductions in mean arterial pressure (MAP) of 5, 10, 20, and 30% below control MAP. Graded constriction of the AA caused large increases in left atrial pressure and plasma atrial natriuretic peptide (ANP), but had no effect on plasma AVP or cortisol and caused only a small increase in PRA at the maximal reduction of MAP. Constriction of the IVC reduced both atrial pressures and plasma ANP, but stimulated increases in PRA, AVP, and cortisol. Constriction of the PA increased right atrial pressure and plasma ANP and caused increases in plasma AVP and cortisol that were similar to responses during IVC constriction, but the PRA response was only half (P < 0.05). These results indicate that increasing pressure on the right side of the heart can attenuate the PRA response to hypotension, and suggest that the inhibition is mediated by the rise in plasma ANP.


1990 ◽  
Vol 259 (3) ◽  
pp. R618-R626 ◽  
Author(s):  
E. W. Quillen ◽  
L. C. Keil ◽  
I. A. Reid

Plasma arginine vasopressin (AVP), plasma renin activity (PRA), and water intake (H2OIN) are increased by thoracic inferior vena caval constriction (TIVCC). To assess the role of the cardiac and sinoaortic baroreceptors in these responses, 9 sham-, 10 cardiac-(CD), 6 sinoaortic-(SAD), and 4 combined cardiac and sinoaortic-(CD + SAD) denervated conscious dogs were studied. All animals were studied while normally hydrated 1) with no access to water (H2O-) and 2) while drinking was permitted (H2O+). TIVCC caused similar reductions (P less than 0.001) of mean arterial (-32 +/- 4 mmHg), left atrial pressure (-6.5 +/- 1.1 cmH2O), and right atrial pressure (-4.2 +/- 0.8 cmH2O) in all groups. After TIVCC in sham dogs with H2O-, AVP increased from 3.6 +/- 0.7 to 72.8 +/- 12.6 pg/ml (P less than 0.001). AVP was similar with SAD (57.1 +/- 6.9) but was reduced with CD (30.9 +/- 3.0) and CD + SAD (17.7 +/- 4.0). In all groups, PRA increased from 4.5 +/- 0.7 to 23.8 +/- 3.0 ng.ml-1 x 3 h-1 and plasma angiotensin II (ANG II) increased from 14.0 +/- 2.8 to 59.5 +/- 13.0 pg/ml (P less than 0.001). Plasma adrenocorticotropic hormone (ACTH) increased similarly in all groups (55 +/- 5 to 128 +/- 25 pg/ml). Plasma norepinephrine (NE) levels increased similarly in all groups (298 +/- 61 to 654 +/- 88 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)


1999 ◽  
Vol 277 (3) ◽  
pp. R795-R801 ◽  
Author(s):  
Terry N. Thrasher ◽  
Craig R. Keenan ◽  
David J. Ramsay

Arterial hypotension stimulates increases in plasma arginine vasopressin (AVP), plasma renin activity (PRA), and water intake in conscious dogs. We have previously reported that increasing left atrial but not right atrial pressure completely blocks the increase in plasma AVP and PRA induced by hypotension. The goal of the present study was to examine the effect of increasing right or left atrial pressure on water intake induced by arterial hypotension. Dogs were prepared with occluding cuffs on the thoracic inferior vena cava, the pulmonary artery, and the ascending aorta. We reduced mean arterial pressure (MAP) 25% below control by either inferior vena cava constriction (IVCC), pulmonary artery constriction (PAC), or ascending aorta constriction (AAC) and measured water intake over a 2-h period. Cumulative water intake during IVCC ( n = 6) and PAC ( n = 6) was 7.8 ± 2.0 and 6.7 ± 2.6 ml/kg, respectively. There was no difference between either the latency or the volume consumed between the two treatments. In contrast, none of the dogs drank during hypotension induced by AAC ( n = 5). Because the degree of arterial baroreceptor unloading was the same in each treatment by design, we conclude that stimulation of left atrial receptors inhibits drinking in response to arterial hypotension but that stimulation of right atrial receptors has no effect on the response in dogs.


1987 ◽  
Vol 62 (1) ◽  
pp. 61-70 ◽  
Author(s):  
D. M. Payen ◽  
C. J. Brun-Buisson ◽  
P. A. Carli ◽  
Y. Huet ◽  
F. Leviel ◽  
...  

Hemodynamic, gas exchange, and hormonal response induced by application of a 25- to 40-mmHg lower body positive pressure (LBPP), during positive end-expiratory pressure (PEEP; 14 +/- 2.5 cmH2O) were studied in nine patients with acute respiratory failure. Compared with PEEP alone, LBPP increased cardiac index (CI) from 3.57 to 4.76 l X min-1 X m-2 (P less than 0.001) in relation to changes in right atrial pressure (RAP) (11 to 16 mmHg; P less than 0.01). Cardiopulmonary blood volume (CPBV) measured in five patients increased during LBPP from 546 +/- 126 to 664 +/- 150 ml (P less than 0.01), with a positive linear relationship between changes in RAP and CPBV (r = 0.88; P less than 0.001). Venous admixture (Qva/QT) decreased with PEEP from 24 to 16% (P less than 0.001) but did not change with LBPP despite the large increase in CI, leading to a marked O2 availability increase (P less than 0.001). Although PEEP induced a significant rise in plasma norepinephrine level (NE) (from 838 +/- 97 to 1008 +/- 139 pg/ml; P less than 0.05), NE was significantly decreased by LBPP to control level (from 1,008 +/- 139 to 794 +/- 124 pg/ml; P less than 0.003). Plasma epinephrine levels were not influenced by PEEP or LBPP. Changes of plasma renin activity (PRA) paralleled those of NE. No change in plasma arginine vasopressin (AVP) was recorded. We concluded that LBPP increases venous return and CPBV and counteracts hemodynamic effects of PEEP ventilation, without significant change in Qva/QT. Mechanical ventilation with PEEP stimulates sympathetic activity and PRA apparently by a reflex neuronal mechanism, at least partially inhibited by the loading of cardiopulmonary low-pressure reflex and high-pressure baroreflex. Finally, AVP does not appear to be involved in the acute cardiovascular adaptation to PEEP.


1995 ◽  
Vol 268 (4) ◽  
pp. R1069-R1077 ◽  
Author(s):  
L. J. Andersen ◽  
J. L. Andersen ◽  
T. N. Thrasher ◽  
L. C. Keil ◽  
D. J. Ramsay

The goal of this study was to test the hypothesis that increasing or decreasing the load on baroreceptors in the right heart influenced the secretion of arginine vasopressin (AVP), adrenocorticotropic hormone (ACTH), and renin during a state of sustained arterial hypotension. The hypothesis was tested in chronically instrumented conscious dogs prepared with inflatable cuffs around the pulmonary artery (PA) and the thoracic inferior vena cava (IVC). In one protocol (n = 5), mean arterial pressure was reduced 10 or 20% below control by constriction of the PA, a maneuver that caused a fall in left atrial pressure (LAP) and an increase in right atrial pressure (RAP). Plasma AVP, ACTH, atrial natriuretic peptide (ANP), and plasma renin activity (PRA) all increased (P < 0.05) in response to constriction of the PA. Reducing RAP to control by constriction of the IVC during maintained constriction of the PA had no effect on MAP, LAP, plasma AVP, ACTH, or PRA, but plasma ANP fell significantly. In a separate protocol (n = 4), constriction of the IVC was used to reduce MAP 10 or 20% below control, and this led to significant decreases in both LAP and RAP and increases in plasma AVP, ACTH, and PRA. RAP was then increased above control by constriction of the PA without altering either MAP or LAP. Raising RAP from a level that was 6.3 +/- 1.3 mmHg below control to 3.5 +/- 1.0 mmHg above control had no effect on plasma AVP, ACTH, or PRA.(ABSTRACT TRUNCATED AT 250 WORDS)


2018 ◽  
Vol 2018 ◽  
pp. 1-3 ◽  
Author(s):  
Sneha R. Gadi ◽  
Benjamin K. Ruth ◽  
Alan Johnson ◽  
Sula Mazimba ◽  
Younghoon Kwon

Inferior vena cava (IVC) diameter and respirophasic variation are commonly used echocardiographic indices to estimate right atrial pressure. While dilatation of the IVC and reduced collapsibility have traditionally been associated with elevated right heart filling pressures, the significance of isolated IVC dilatation in the absence of raised filling pressures remains poorly understood. We present a case of an asymptomatic 28-year-old male incidentally found to have IVC dilatation, reduced inspiratory collapse, and normal right heart pressures.


1987 ◽  
Vol 65 (2) ◽  
pp. 257-259 ◽  
Author(s):  
Susan Kaufman

Rats were prepared with inflatable balloons at the superior vena cava – right atrium junction. After recovery 1 week later, when blood was taken from conscious, normovolaemic animals plasma renin activity was found not to be influenced by right atrial stretch. Plasma renin activity was then measured in rats in which an extracellular fluid deficit had been produced by peritoneal dialysis against a hyperoncotic, isotonic solution. Although basal plasma renin activity was elevated (6.8 ± 0.9 from 1.5 ± 0.2 ng∙mL∙h, n = 19), no depression was observed in the experimental group after 15 or 90 min of balloon inflation. In rats pretreated with isoprenaline (10 μg/kg body wt.) plasma renin activity was also increased over basal levels, but again balloon inflation caused no reduction in plasma renin activity. It would appear that right atrial stretch has little, if any, influence on renin release in the conscious rat.


2000 ◽  
Vol 279 (3) ◽  
pp. H1201-H1207 ◽  
Author(s):  
Masato Tsuboi ◽  
Yasuyuki Furukawa ◽  
Koichi Nakajima ◽  
Fumio Kurogouchi ◽  
Shigetoshi Chiba

Some parasympathetic ganglionic cells are located in the epicardial fat pad between the medial superior vena cava and the aortic root (SVC-Ao fat pad) of the dog. We investigated whether the ganglionic cells in the SVC-Ao fat pad control the right atrial contractile force, sinus cycle length (SCL), and atrioventricular (AV) conduction in the autonomically decentralized heart of the anesthetized dog. Stimulation of both sides of the cervical vagal complexes (CVS) decreased right atrial contractile force, increased SCL, and prolonged AV interval. Stimulation of the rate-related parasympathetic nerves to the sinoatrial (SA) node (SAPS) increased SCL and decreased atrial contractile force. Stimulation of the AV conduction-related parasympathetic nerves to the AV node prolonged AV interval. Trimethaphan, a ganglionic nicotinic receptor blocker, injected into the SVC-Ao fat pad attenuated the negative inotropic, chronotropic, and dromotropic responses to CVS by 33∼37%. On the other hand, lidocaine, a sodium channel blocker, injected into the SVC-Ao fat pad almost totally inhibited the inotropic and chronotropic responses to CVS and partly inhibited the dromotropic one. Lidocaine or trimethaphan injected into the SAPS locus abolished the inotropic responses to SAPS, but it partly attenuated those to CVS, although these treatments abolished the chronotropic responses to SAPS or CVS. These results suggest that parasympathetic ganglionic cells in the SVC-Ao fat pad, differing from those in SA and AV fat pads, nonselectively control the atrial contractile force, SCL, and AV conduction partially in the dog heart.


2017 ◽  
Vol 23 (10) ◽  
pp. S39
Author(s):  
Akiko Idemoto ◽  
Haruhiko Abe ◽  
Kaori Yasumura ◽  
Hiroki Nishida ◽  
Taishi Kato ◽  
...  

1990 ◽  
Vol 69 (3) ◽  
pp. 924-931 ◽  
Author(s):  
M. L. Cohen

Seven episodes of experimental cardiac tamponade were induced in five anesthetized closed-chest dogs. Simultaneous pericardial and intracavitary pressures were synchronized with superior vena caval and transvalvular pulsed-Doppler flow tracings. The earliest indication of tamponade was the development of a negative transmural right atrial pressure that occurred during early ventricular diastole and was associated with echocardiographic evidence of right atrial collapse. This was also associated with reversal of diastolic flow in the superior vena cava and with diminished early diastolic flow velocity across the tricuspid as well as the mitral valve. During more advanced cardiac tamponade, the transmural right atrial pressure became negative during both early and late ventricular diastole as well as during isovolumic ventricular systole. This was associated with a disappearance of early diastolic ventricular filling and right ventricular diastolic collapse as observed on two-dimensional echocardiography. In hypotensive cardiac tamponade (cardiac output diminished by 70%), the decreased transmural right atrial pressure that developed during ventricular systole was accompanied by diminished antegrade flow in the superior vena cava. In advanced and hypotensive tamponade, ventricular filling occurred mainly during atrial contraction.


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