Enhancement of the Antihypertensive Effect of Hydrochlorothiazide in Dogs after Suppression of Renin Release by Beta-Adrenergic Blockade

1975 ◽  
Vol 48 (2) ◽  
pp. 147-151
Author(s):  
C. S. Sweet ◽  
M. Mandradjieff
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Antihypertensive Effect ◽  
Plasma Renin ◽  
Renin Activity ◽  
Renin Release ◽  
Antihypertensive Activity ◽  
Adrenergic Blockade ◽  
Arterial Blood

1. Renal hypertensive dogs were treated with hydrochlorothiazide (8−2 μmol/kg or 33 μmol/kg daily for 7 days), or timolol (4.6 μmol/kg daily for 4 days), a potent β-adrenergic blocking agent, or combinations of these drugs). Changes in mean arterial blood pressure and plasma renin activity were measured over the treatment period. 2. Neither drug significantly lowered arterial blood pressure when administered alone. Plasma renin activity, which did not change during treatment with timolol, was substantially elevated during treatment with hydrochlorothiazide. 3. When timolol was administered concomitantly with hydrochlorothiazide, plasma renin activity was suppressed and blood pressure was significantly lowered. 4. These observations suggest that compensatory activation of the renin-angiotensin system limits the antihypertensive activity of hydrochlorothiazide in renal hypertensive dogs and suppression of diuretic-induced renin release by timolol unmasks the antihypertensive effect of the diuretic.

Hormonal responses to synthetic atrial natriuretic peptide in patients on regular hemodialysis

1988 ◽  
Vol 119 (2) ◽  
pp. 257-262 ◽  
Author(s):  
Sadao Nakajima ◽  
Hiromichi Suzuki ◽  
Yo Kageyama ◽  
Takashi Takita ◽  
Takao Saruta
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Arterial Blood ◽  
Sympathetic Nervous ◽  
Regular Hemodialysis

Abstract. The effects of atrial natriuretic peptide (ANP) on mean arterial blood pressure, heart rate, plasma renin activity, aldosterone, cortisol, norepinephrine, epinephrine and arginine vasopressin were studied in 6 anuric subjects receiving regular hemodialysis. An iv bolus injection of 8 nmol of ANP followed by infusion at 32 pmol·kg−1·min−1 for 1 h in the pre- and posthemodialysis period was performed. Basal plasma ANP was higher before than after hemodialysis. ANP administration produced a reduction in mean arterial blood pressure accompanied by an elevation of norepinephrine and of plasma renin activity (from 2.49 ± 0.52 to 3.39 ± 0.85 nmol·l−1·h−1 predialysis and from 2.78 ± 0.71 to 3.15 ± 0.86 nmol·l−1·h−1 postdialysis, respectively, mean ± sem; P < 0.05). Plasma aldosterone and cortisol were significantly decreased. Plasma epinephrine and AVP remained unchanged. These hemodynamic and hormonal changes were similar in the pre- and the postdialysis period. These results suggest that 1) ANP causes a fall in mean arterial blood pressure, which in turn induces reflex tachycardia and activation of the sympathetic nervous system without diuresis; 2) the activated sympathetic nervous system as reflected in elevation of plasma norepinephrine may increase plasma renin activity; 3) reduced plasma aldosterone is not influenced by enhancement of the reninangiotensin system; therefore, 4) reduction of plasma aldosterone as well as cortisol is probably due to direct action of ANP, and finally 5) AVP had no direct relation with ANP administration.

Antagonism of Hydrochlorothiazide-Induced Elevations in Plasma-Renin Activity by Methyldopa in Conscious Renal-Hypertensive Dogs

1974 ◽  
Vol 52 (5) ◽  
pp. 1036-1040 ◽  
Author(s):  
Charles S. Sweet ◽  
Herbert C. Wenger ◽  
Theresa A. O'Malley
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Treatment Period ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Day Treatment ◽  
Plasma Renin ◽  
Significant Decline ◽  
Renin Activity ◽  
Arterial Blood

Hydrochlorothiazide, 2.5 and 10 mg/kg per day, was administered alone and in combination with methyldopa, 200 mg/kg per day, and changes in plasma-renin activity and mean arterial blood pressure were measured in conscious hypertensive dogs during a 7-day treatment period. Hydrochlorothiazide did not lower mean arterial blood pressure although there was a substantial increase in plasma-renin activity. When methyldopa was administered in combination with hydrochlorothiazide, a significant decline in both blood pressure and plasma-renin activity was observed. Since methyldopa was hypotensive only when coadministered with hydrochlorothiazide, the results suggest that antihypertensive effects of methyldopa in the diuretic-treated dog may depend in part on suppression of renin release.

Acute Effect of Plasma Exchange on Arterial Blood Pressure and Plasma Renin Activity

1985 ◽  
Vol 9 (3) ◽  
pp. 276-279 ◽  
Author(s):  
L. Moriconi ◽  
C. Palombo ◽  
E. Fommei ◽  
P. Meconi ◽  
R. Puccini ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Plasma Exchange ◽  
Arterial Blood Pressure ◽  
Plasma Renin ◽  
Acute Effect ◽  
Renin Activity ◽  
Arterial Blood

Response of Arterial Blood Pressure, Plasma Renin Activity and Plasma Aldosterone Concentration to Long-Term Administration of Captopril in Patients with Severe, Treatment-Resistant Malignant Hypertension

1979 ◽  
Vol 57 (s5) ◽  
pp. 371s-373s ◽  
Author(s):  
Connie S. McCaa ◽  
H.G. Langford ◽  
W. C. Cushman ◽  
R. E. McCaa
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Antihypertensive Therapy ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Treatment Resistant ◽  
Plasma Aldosterone Concentration ◽  
Arterial Blood

1. The response of arterial blood pressure, plasma renin activity and plasma aldosterone concentration to inhibition of angiotensin I converting enzyme (kininase II) with captopril has been studied in patients with severe, treatment-resistant, malignant hypertension. 2. Nine patients with a past history of severe hypertension, supine diastolic blood pressure &gt; 120 mmHg before conventional antihypertensive therapy and resistant to conventional antihypertensive therapy were studied. 3. Captopril administration resulted in a marked decrease in arterial blood pressure and plasma aldosterone concentration and an increase in plasma renin activity. 4. Although arterial blood pressure remained significantly below the values observed during the control period, pressure did tend to increase again after 3 days. Addition of hydrochlorothiazide kept arterial pressure significantly below pretreatment control values.

Effect of angiotensin II and of an Angiotensin II Analogue (Sar1-Ile8-Angiotensin II) on Blood Pressure, Plasma Aldosterone and Plasma Renin Activity in the Dog

1974 ◽  
Vol 48 (s2) ◽  
pp. 41s-44s
Author(s):  
R. Beckerhoff ◽  
G. Uhlschmid ◽  
W. Vetter ◽  
H. Armbruster ◽  
J. Nussberger ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Angiotensin Receptors ◽  
Pressure Plasma ◽  
Arterial Blood

1. The effect of infusions of equimolar doses of angiotensin II (AII) and of the angiotensin analogue Sar1-Ile8-angiotensin II on arterial blood pressure, plasma aldosterone and plasma renin activity were compared in normal anaesthetized dexamethasone suppressed dogs. 2. Angiotensin II induced a significant increase of blood pressure and of plasma aldosterone whereas plasma renin activity decreased. The blood pressure was only slightly affected by large doses of the analogue. Plasma aldosterone, however, increased and plasma renin activity decreased. These changes were significant but less pronounced than after the infusions of angiotensin II. Plasma aldosterone remained high and renin activity low for 40 min after the infusions of the analogue. 3. The results suggest a strong agonistic potency of Sar1-Ile8-angiotensin II at the adrenal and renal angiotensin receptors, and that it is almost ineffective at the vascular receptors. The inhibition of renin secretion by angiotensin seems not to be related to its vasoconstrictive activity.

Arterial pressure after chronic reductions in suprarenal aortic flow in fetal lambs

1987 ◽  
Vol 253 (4) ◽  
pp. H838-H844
Author(s):  
D. F. Anderson ◽  
C. M. Parks ◽  
J. J. Faber
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Plasma Renin ◽  
Aortic Flow ◽  
Renin Activity ◽  
Upper Body ◽  
Aortic Blood Flow ◽  
Arterial Blood

Experiments were performed on 13 fetal lambs of 126 days gestational age. Seven days after surgery, suprarenal aortic blood flow was reduced to 70% of control with an inflatable occluder for a period of at least 4 days. This produced an almost constant aortic pressure difference of 35 mmHg across the occluder. Plasma renin activity (PRA) rose in the next hour from 6 to 42 ng.ml-1.h-1 (P less than 0.01) but decreased to a level that was statistically insignificantly above normal by the next day. PRA as a function of lower body arterial blood pressure showed rapid adaptation. Upper body arterial blood pressure was statistically significantly elevated by 5 mmHg within 5 min and continued to rise while plasma renin activity was falling. Femoral artery blood pressure dropped immediately but returned to near normal within 1 h and remained there. The long-term upper body hypertension was irreversible with a 30-min infusion of saralasin. Subrenal aortic flow reduction caused none of these changes. We conclude that the fetal kidneys can regulate arterial blood pressure upward but that the long-term effect does not depend solely on a direct vasoconstrictive action of angiotensin.

Reflex inhibition of plasma renin activity by increased left ventricular pressure in conscious dogs

1989 ◽  
Vol 256 (6) ◽  
pp. R1299-R1307
Author(s):  
A. J. Gorman ◽  
J. S. Chen
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Plasma Renin Activity ◽  
Arterial Blood Pressure ◽  
Left Atrial ◽  
Plasma Renin ◽  
Left Ventricular ◽  
Renin Activity ◽  
Conscious Dogs ◽  
Arterial Blood

The purpose of the present study was to determine the effects of left ventricular (LV) outflow obstruction on plasma renin activity (PRA) and the contribution from afferent receptors located in the LV myocardium. In chronically instrumented, conscious dogs (n = 12), changes in PRA during a 15- to 20-mmHg decrease in arterial blood pressure were assessed during 1) intravenous infusions of nitroprusside (NP) alone and 2) infusions of NP while peak systolic LV pressure was elevated by acute ascending aortic occlusion (AAO + NP). Infusions of NP alone elicited significant increases in heart rate (24.9 +/- 5.1 beats/min; P less than 0.01) and in PRA [3.31 +/- 0.53 ng angiotensin I (ANG I).ml-1.h-1; P less than 0.01]. These were accompanied by decreases in both LV pressure (-13.8 +/- 3.6 mmHg; P less than 0.05) and left atrial pressure (-3.0 +/- 0.7 mmHg; P less than 0.05). During AAO + NP, LV pressure was elevated to an absolute level of 169.2 +/- 4.6 mmHg (+53.3 +/- 4.2 mmHg; P less than 0.001), whereas left atrial pressure was not changed. Both the hypotension-induced rise in PRA and tachycardia were significantly inhibited during AAO + NP (+0.59 +/- 0.29 ng ANG I.ml-1.h-1 and +6.3 +/- 4.6 beats/min, respectively; NS). The topical application of a local anesthetic in the region of the main coronary artery, sufficient to block the heart rate and arterial blood pressure responses to selective LV receptor stimulation by intracoronary veratridine (0.1-0.4 microgram/kg), resulted in significant increases in PRA and heart rate during AAO + NP.(ABSTRACT TRUNCATED AT 250 WORDS)

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