Renal perfusion pressure and renin secretion in the rainbow trout, Salmo gairdneri

1981 ◽  
Vol 59 (7) ◽  
pp. 1220-1226 ◽  
Author(s):  
J. R. Bailey ◽  
D. J. Randall

In the trout, Salmo gairdneri, a significant correlation between the amount of blood loss and plasma renin activity was established. This increase in plasma renin activity could be due to stimulation of an intrarenal receptor, thus an isolated nonfiltering perfused kidney preparation was developed to test this hypothesis. It was found that a decrease in renal perfusion pressure resulted in an increase in renin release (as measured by perfusate renin activity) but an increase in renal perfusion pressure had no effect on renin release. The increase in renin secretion in response to a decreased renal perfusion pressure was not affected by sympathetic nervous system blocking agents, whereas angiotensin II will apparently inhibit renin secretion in vitro. It was concluded that a baroreceptor response, similar to that found in mammals, is found in fishes and a model mechanism for renin secretion in fishes is proposed.

1976 ◽  
Vol 51 (s3) ◽  
pp. 109s-111s ◽  
Author(s):  
I. A. Reid ◽  
A. Jones

1. Sympathetic reflexes were activated by carotid occlusion in anaesthetized dogs in which changes in renal perfusion pressure were prevented. This produced a prompt and reversible increase in plasma renin activity. 2. Administration of clonidine decreased plasma renin activity, arterial pressure and heart rate and blocked the renin secretory and blood pressure responses to carotid occlusion. 3. These results support the hypothesis that the suppression of renin secretion by clonidine is a consequence of the decrease in sympathetic activity produced by this drug.


1994 ◽  
Vol 266 (6) ◽  
pp. R1723-R1729 ◽  
Author(s):  
R. A. Johnson ◽  
R. H. Freeman

The influence of renal perfusion pressure on renin release was examined in rats administered the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME). Compared with the control plasma renin of 6.0 +/- 0.7 ng angiotensin I (ANG I).ml-1.h-1, plasma renin activity was suppressed (1.8 +/- 0.2 ng ANG I.ml-1.h-1, P < 0.05) in L-NAME-treated animals in which the renal perfusion pressure was permitted to increase and reached 141 +/- 8 mmHg. Plasma renin activity also was suppressed (2.5 +/- 0.4 ng ANG I.ml-1.h-1, P < 0.05) in a second L-NAME-treated group in which the renal perfusion pressure was controlled to a level of 105 +/- 5 mmHg via tightening of a suprarenal aortic snare. Plasma renin activity was increased (12.0 +/- 1.4 ng ANG I.ml-1.h-1, P < 0.05) in a third L-NAME-treated group in which renal perfusion pressure was reduced to 59 +/- 1 mmHg. Overall, these findings suggest that the intrarenal pressure-sensing mechanism for renin release does not stringently require nitric oxide synthesis. In a second experimental series, bilaterally renal-denervated rats were administered L-NAME, and again plasma renin activity was suppressed significantly whether renal perfusion pressure was permitted to increase or was controlled. Thus L-NAME also suppressed plasma renin activity independently of reflex reductions in renal neuroadrenergic activity even when renal perfusion pressure was controlled. Infusions of sodium nitroprusside completely inhibited L-NAME-induced suppression of plasma renin activity in these renal-denervated rats. Nitric oxide may function as a paracrine stimulatory mechanism for the local regulation of renin release.


1992 ◽  
Vol 262 (3) ◽  
pp. R524-R529 ◽  
Author(s):  
N. D. Binder ◽  
D. F. Anderson

We examined the relationship between acute reductions in renal perfusion pressure, as approximated by femoral arterial blood pressure, and plasma renin activity in the uninephrectomized fetal lamb. Renal perfusion pressure was reduced and maintained at a constant value by controlled partial occlusion of the aorta above the renal artery. After 15 min of reduced blood pressure, blood samples were taken for determination of plasma renin activity. This protocol was performed 22 times in 11 fetal lambs. Additionally, three of the fetuses were delivered by cesarean section and studied as newborns for the first week of life. In the fetus, there was a linear relationship between log plasma renin activity and femoral arterial blood pressure (P less than 0.01). After birth, the relationship still existed, although it was shifted to the right (P less than 0.0001). We conclude that there is a significant relationship between plasma renin activity and renal perfusion pressure in the fetal lamb, and as early as 1 day after birth, this relationship shifts to the right in the newborn lamb.


1979 ◽  
Vol 236 (6) ◽  
pp. H854-H859 ◽  
Author(s):  
M. D. Johnson ◽  
E. R. Fahri ◽  
B. R. Troen ◽  
A. C. Barger

Previous work from our laboratory has shown that physiological increments of circulating epinephrine concentration increase plasma renin activity (PRA) by an extrarenal beta-receptor mechanism. In the present experiments, epinephrine was infused intravenously at 125 ng.kg-1.min-1 for 45 min in trained, conscious dogs. PRA rose 3 to 5-fold, as previously described, and was accompanied by a transient decline of mean arterial pressure, decreased plasma potassium concentration, and increased hematocrit. Prior splenectomy to maintain hematocrit constant did not attenuate the PRA response to epinephrine. The kidneys of 4 dogs were denervated and constrictor cuff was placed around the renal artery. Renal denervation did not alter the PRA response to intravenous epinephrine infusion. A transient decline in renal perfusion pressure produced by cuff constriction only transiently increase PRA. Neither maintenance of a constant plasma potassium concentration nor oral administration of indomethacin altered the PRA response to epinephrine. We conclude that intravenous epinephrine increases PRA by a mechanism independent of the renal nerves, changes in renal perfusion pressure, hematocrit, plasma potassium concentration, and plasma prostaglandins.


1984 ◽  
Vol 247 (3) ◽  
pp. R546-R551 ◽  
Author(s):  
D. Villarreal ◽  
J. O. Davis ◽  
R. H. Freeman ◽  
W. D. Sweet ◽  
J. R. Dietz

This study examines the role of the renal prostaglandin system in stimulus-secretion coupling for renal baroreceptor-dependent renin release in the anesthetized rat. Changes in plasma renin activity (PRA) secondary to suprarenal aortic constriction were evaluated in groups of rats with a single denervated nonfiltering kidney (DNFK) with and without pretreatment with meclofenamate. Suprarenal aortic constriction was adjusted to reduce renal perfusion pressure to either 100 or 50 mmHg. In addition, similar experiments were performed in rats with a single intact filtering kidney. Inhibition of prostaglandin synthesis with meclofenamate failed to block or attenuate the increase in PRA in response to the decrement in renal perfusion pressure after both severe and mild aortic constriction for both the DNFK and the intact-kidney groups. The adequacy of prostaglandin inhibition was demonstrated by complete blockade with meclofenamate of the marked hypotensive and hyperreninemic responses to sodium arachidonate. The results in the DNFK indicate that in the rat, renal prostaglandins do not function as obligatory mediators of the isolated renal baroreceptor mechanism for the control of renin release. Also the findings in the intact filtering kidney suggest that prostaglandins are not essential in the renin response of other intrarenal receptor mechanisms that also are stimulated by a reduction in renal perfusion pressure.


1994 ◽  
Vol 72 (7) ◽  
pp. 782-787 ◽  
Author(s):  
L. Fan ◽  
S. Mukaddam-Daher ◽  
J. Gutkowska ◽  
B. S. Nuwayhid ◽  
E. W. Quillen Jr.

To further investigate the influence of renal nerves on renin secretion, the renin secretion responses to step reductions of renal perfusion pressure (RPP) were studied in conscious sheep with innervated kidneys (n = 5) and with bilaterally denervated kidneys (n = 5). The average basal level of RPP in sheep with denervated kidneys (82 ± 4 mmHg; 1 mmHg = 133.3 Pa) was similar to that in sheep with innervated kidneys (83 ± 3 mmHg). RPP was reduced in four sequential 15-min steps, to a final level of 54 ± 2 mmHg in sheep with innervated kidneys and to 57 ± 1 mmHg in denervated sheep. The renin secretion rate was increased as RPP was reduced in sheep with innervated kidneys. Baseline peripheral plasma renin activity was reduced and there was almost no response of renin secretion rate to reduction of RPP in sheep with denervated kidneys. Also, baseline renal blood flow, urine flow rate, sodium excretion rate, and potassium excretion rate were higher in sheep with denervated kidneys than those with innervated kidneys. Baseline plasma angiotensin II was similar in both groups of sheep. As RPP was decreased, plasma angiotensin II was increased in sheep with innervated kidneys, but was not significantly altered in sheep with denervated kidneys. Plasma atrial natriuretic factor was unaltered by either reduction of RPP or renal denervation. In conclusion, hormonal factors, such as angiotensin II and atrial natriuretic factor, do not account for the dramatic suppression of renin secretion in response to the reduction of RPP in sheep with bilateral renal denervation. Renal nerves are a necessary component in the control of renin secretion during reduction of RPP and may contribute to the regulation of baseline plasma renin activity and sodium excretion rate in conscious ewes.Key words: renin secretion, renal perfusion pressure, renal nerves, denervation, sheep.


1976 ◽  
Vol 51 (s3) ◽  
pp. 271s-274s
Author(s):  
P. C. Weber ◽  
C. Larsson ◽  
M. Hamberg ◽  
E. Änggård ◽  
E. J. Corey ◽  
...  

1. The prostaglandin precursor arachidonic acid (C20:4) increases plasma renin activity in the rabbit and rat when it is infused into the renal arteries. 2. The increase in plasma renin activity after C20:4 in rats is not changed by volume expansion. 3. The inhibitor of prostaglandin synthesis indomethacin decreases plasma renin activity in the rabbit. 4. The increase in plasma renin activity after total renal ischaemia is abolished by pretreatment with indomethacin. 5. C20:4 increases dose- and time-dependent renin release from slices of rabbit kidney cortex. 6. Indomethacin or 5,8,11,14-eicosatetraynoic acid pretreatment in vivo, and addition to the incubation medium, reduces basal as well as C20:4-stimulated renin release in vitro. 7. The stimulating effect of C20:4 on renin release is assumed to be caused directly by formation of prostaglandin endoperoxides in the kidney cortex and not by prostaglandins since in vitro a natural prostaglandin endoperoxide (PGG2) and two stable synthetic prostaglandin endoperoxide analogues (EPA I and EPA II) do increase the release of renin, but PGE2 has no effect and PGF2α inhibits renin release.


1977 ◽  
Vol 53 (5) ◽  
pp. 447-452
Author(s):  
J. C. S. Fray ◽  
P. V. H. Mayer

1. We have examined the response of renin to chronic low and high sodium chloride intake in rats with transplanted phaeochromocytoma. 2. Phaeochromocytoma suppressed the usual elevated plasma renin activity observed during sodium deprivation. 3. Studies in isolated perfused kidneys indicated that sodium-deprived phaeochromocytoma rats released substantially less renin than sodium-deprived control rats despite an almost identical renal renin content in both sets of animals. In addition, low perfusion pressure (50 mmHg) failed to stimulate renin release in kidneys from these phaeochromocytoma rats. 4. Additional experiments demonstrated that chronic sodium chloride loading suppressed plasma renin activity, renin content and renin release in both phaeochromocytoma and control rats. Both sodium-loaded phaeochromocytoma and sodium-loaded control rats were unresponsive to low perfusion pressure. 5. We conclude that noradrenaline-secreting phaeochromocytoma impairs the response of plasma renin activity in the rat by inhibiting renin release. We also conclude that chronic sodium chloride loading has a similar effect, but the mechanisms remain to be determined.


1995 ◽  
Vol 268 (2) ◽  
pp. F296-F301
Author(s):  
E. W. Quillen ◽  
I. A. Reid

Studies were performed to determine whether intravertebral angiotensin II infusion (iva ANG II) decreases renin release by increasing renal perfusion pressure (RPP) and to investigate possible effects of iva ANG II on renal function. RPP was electronically servocontrolled in 12 conscious dogs equipped with chronic vascular catheters and a suprarenal aortic balloon constrictor while iva ANG II was infused bilaterally for 60 min at 0.33 ng.kg-1.min-1. Without servocontrol, iva ANG II increased mean arterial pressure (MAP) from 101 +/- 4 to 106 +/- 5 mmHg, urine flow (V) from 0.36 +/- 0.03 to 0.45 +/- 0.04 ml/min, and sodium excretion (UNaV) from 36.2 +/- 7.0 to 62.7 +/- 6.6 mumol/min. Plasma renin activity (PRA) decreased from 6.9 +/- 0.7 to 5.0 +/- 0.6 ng ANG I.ml-1.3 h-1. With servocontrol, iva ANG II increased MAP from 102 +/- 4 to 109 +/- 5 mmHg while RPP remained constant with a variation of less than +/- 1 mmHg. PRA did not change significantly (5.9 +/- 0.3 to 7.0 +/- 0.7 ng ANG I.ml-1.3 h-1). V decreased from 0.33 +/- 0.02 to 0.26 +/- 0.01 ml/min, and UNaV decreased from 49.0 +/- 5.7 to 29.7 +/- 4.4 mumol/min. The data provide evidence that iva ANG II decreases renin release by increasing RPP and stimulating the renal baroreceptor and/or the macula densa mechanisms. In addition, at constant RPP, ANG II exerts a central action to decrease UNaV.


1980 ◽  
Vol 239 (1) ◽  
pp. F44-F49 ◽  
Author(s):  
T. A. Kotchen ◽  
K. E. Krzyzaniak ◽  
J. E. Anderson ◽  
C. B. Ernst ◽  
J. H. Galla ◽  
...  

To determine if inhibition of renin release by HCl is related to acidosis or to Cl-, the effects of peripheral venous infusions of HCl and H2SO4 on plasma renin activity (PRA) were compared in the dog and the rat. In NaCl-deprived, pentobarbital-anesthetized dogs, either 0.15 M HCl (n = 10) or 0.075 M H2SO4 (n = 7) was infused for 60 min. In 5 of the 10 HCl-infused dogs (group A), urine Cl- excretion increased (P less than 0.01) during HCl infusion. In the remaining five dogs (group B), Cl- excretion did not increase. Cl- excretion also did not increase during H2SO4 infusion. Comparable acidosis was produced in all three groups. PRA decreased (P less than 0.01) in response to HCl in group A but did not change (P greater than 0.8) in group B HCl-infused dogs or in H2SO4-infused dogs. In NaCl-deprived, anesthetized rats, PRA was suppressed (P less than 0.05) by HCl (from 40.6 +/- 9.4 to 27.4 +/- 5.3 ng . ml-1 . h-1 (SE)) but not H2SO4 (from 37.1 +/- 4.2 to 37.0 +/- 6.3 ng . ml-1 . h-1), despite comparable acidosis. Cl- excretion increased only in HCl-infused rats. In conclusion, inhibition of PRA by acute infusion of HCl is specifically related to Cl-.


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