scholarly journals Role of the renin-angiotensin system in blood pressure regulation. The cardiovascular effects of converting enzyme inhibition in normotensive subjects.

1979 ◽  
Vol 45 (6) ◽  
pp. 829-837 ◽  
Author(s):  
A P Niarchos ◽  
T G Pickering ◽  
D B Case ◽  
P Sullivan ◽  
J H Laragh
Keyword(s):  
Blood Pressure ◽  
Enzyme Inhibition ◽  
Renin Angiotensin System ◽  
Cardiovascular Effects ◽  
Pressure Regulation ◽  
Converting Enzyme ◽  
Angiotensin System ◽  
Converting Enzyme Inhibition ◽  
Normotensive Subjects

Responses to converting-enzyme inhibition and hemorrhage in newborn lambs and adult sheep

1987 ◽  
Vol 252 (2) ◽  
pp. R306-R313
Author(s):  
J. C. Rose ◽  
S. M. Block ◽  
K. Flowe ◽  
M. Morris ◽  
S. South ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Enzyme Inhibition ◽  
Age Groups ◽  
Renin Angiotensin System ◽  
Angiotensin Converting Enzyme Inhibition ◽  
Converting Enzyme ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Adult Sheep ◽  
Converting Enzyme Inhibition

We compared the cardiovascular and hormonal responses to angiotensin converting enzyme inhibition and hemorrhage of 20% of blood volume in chronically instrumented unanesthetized newborn lambs and adult sheep. Administration of the nonsulfhydryl-containing converting-enzyme inhibitor enalapril reduced mean arterial pressure in the newborn but not in the adult animals. Blood pressure fell in both age groups after hemorrhage, and the hemorrhage-induced fall in blood pressure, integrated over the period of hypovolemia, was more pronounced when converting-enzyme inhibition was present in the lambs. This was not observed in the adults. Cardiac output fell following hemorrhage in both age groups, and the fall was greater when enalapril was present in the lambs, but this was not the case in the adults. Hemorrhage increased plasma renin activity in both groups, and enalapril augmented this increase. Plasma concentrations of vasopressin and catecholamines increased following hemorrhage within and between groups. Taken together these data suggest that the renin-angiotensin system plays a more important role in the maintenance of cardiovascular homeostasis in newborn lambs than it does in adult sheep, and catecholamine and vasopressin responses to volume loss can occur in the presence of blockade of the renin-angiotensin system.

Renin-angiotensin system, converting-enzyme inhibition and kidney function in aging female rats

1986 ◽  
Vol 251 (3) ◽  
pp. R450-R455 ◽  
Author(s):  
B. Corman ◽  
J. B. Michel
Keyword(s):  
Blood Pressure ◽  
Enzyme Activity ◽  
Enzyme Inhibition ◽  
Renin Angiotensin System ◽  
Converting Enzyme ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Converting Enzyme Inhibition ◽  
Old Rats ◽  
Pah Clearance

The age-related changes in the renin-angiotensin system were investigated in normotensive 3-, 10-, 20-, and 30-mo-old female Wistar rats. Plasma renin concentration and immunofluorescent renal renin index remained constant from 3 to 10 mo, then decreased as the animals become older, whereas plasma concentration of renin substrate diminished slightly between 10 and 20 mo and plasma converting-enzyme activity was not modified with age. Acute inhibition of converting-enzyme activity by intravenous administration of 0.1 mg/100 g body wt S 9780 (the diacid form of S 9490) was followed by a 7- to 8-mmHg decrease in arterial pressure and a concomitant 10-12% increase in inulin and p-aminohippuric acid (PAH) clearance in the 10- and 20-mo-old rats. On the other hand, neither glomerular filtration rate, PAH clearance nor arterial blood pressure were affected by converting-enzyme inhibition in the 30 mo-old rats. These results indicate that the activity of the renin-angiotensin system is progressively reduced with age and suggest that angiotensin II does not play an important role in the maintenance of blood pressure and kidney hemodynamics in normotensive female senescent rats.

Brain angiotensin receptors and sympathoadrenal regulation during insulin-induced hypoglycemia

2001 ◽  
Vol 280 (4) ◽  
pp. R1162-R1168 ◽  
Author(s):  
René H. Worck ◽  
Dennis Staahltoft ◽  
Thomas E. N. Jonassen ◽  
Erik Frandsen ◽  
Hans Ibsen ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Enzyme Inhibition ◽  
Blood Pressure Response ◽  
Pressure Response ◽  
Angiotensin Receptors ◽  
Converting Enzyme ◽  
Reflex Regulation ◽  
Conscious Rats ◽  
Converting Enzyme Inhibition

Simultaneous blockade of systemic AT1 and AT2 receptors or converting enzyme inhibition (CEI) attenuates the hypoglycemia-induced reflex increase of epinephrine (Epi). To examine the role of brain AT1 and AT2 receptors in the reflex regulation of Epi release, we measured catecholamines, hemodynamics, and renin during insulin-induced hypoglycemia in conscious rats pretreated intracerebroventricularly with losartan, PD-123319, losartan and PD-123319, or vehicle. Epi and norepinephrine (NE) increased 60-and 3-fold, respectively. However, the gain of the reflex increase in plasma Epi (Δplasma Epi/Δplasma glucose) and the overall Epi and NE responses were similar in all groups. The ensuing blood pressure response was similar between groups, but the corresponding bradycardia was augmented after PD-123319 ( P < 0.05 vs. vehicle) or combined losartan and PD-123319 ( P < 0.01 vs. vehicle). The findings indicate 1) brain angiotensin receptors are not essential for the reflex regulation of Epi release during hypoglycemia and 2) the gain of baroreceptor-mediated bradycardia is increased by blockade of brain AT2 receptors in this model.

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