The Inhibition of Renin Secretion by Alpha-Adrenergic Stimulation in the Isolated Rat Kidney

1974 ◽  
Vol 47 (5) ◽  
pp. 471-479 ◽  
Author(s):  
R. Vandongen ◽  
W. S. Peart

1. The respective role of alpha-adrenergic and beta-adrenergic receptors in mediating the effect of catecholamines on renin secretion was examined in the isolated perfused rat kidney. 2. Noradrenaline, which has combined alpha- and beta-adrenergic activity, stimulated renin secretion only in the presence of the alpha-receptor blocking agent phenoxybenzamine. This stimulatory effect was largely prevented by the addition of the beta-blocking agent, propranolol. The vasoconstrictor action of noradrenaline, and thus the rise in mean renal perfusion pressure, was abolished by phenoxybenzamine. Our previous finding that noradrenaline alone stimulated renin release was inconclusive (Vandongen, Peart & Boyd, 1973). 3. Noradrenaline stimulated renin secretion when calcium was excluded from the perfusion fluid, to which disodium EDTA (25 mmol/l) was added. The vasoconstrictor action of noradrenaline was considerably attenuated under these conditions. 4. Methoxamine, which has only alpha-adrenergic activity, did not increase renin secretion when infused alone or with phenoxybenzamine. The increase in renin secretion after beta-adrenergic stimulation with isoproterenol was significantly suppressed by methoxamine, although this was associated with an increase in mean renal perfusion pressure. 5. These findings indicate the importance of intrarenal beta-adrenergic receptors in the stimulation of renin secretion and suggest that an opposite inhibitory effect on renin secretion follows alpha-adrenergic activity. 6. Although the results do not exclude a direct effect of vascular tone and renal perfusion pressure, it is suggested that the stimulation and inhibition of renin secretion is related to smooth muscle activity by the involvement of a calcium-dependent process similar to that involved in contraction and relaxation. This would accord with the common derivation of the renin-producing and vascular smooth muscle cells

1979 ◽  
Vol 57 (s5) ◽  
pp. 161s-163s
Author(s):  
R. Vandongen ◽  
K. D. Strang ◽  
Marianne H. Poesse ◽  
W. H. Birkenhager

1. The effect of α-adrenergic stimulation, with phenylephrine, on isoprenaline-provoked renin secretion was studied in the isolated perfused rat kidney. 2. Infusion of phenylephrine increased renal perfusion pressure and prevented renin secretion in response to isoprenaline. 3. Renal vasoconstriction was abolished and the response in renin secretion to isoprenaline was restored by α-adrenoreceptor blockade with phenoxybenzamine. 4. In contrast, when renal vasoconstriction was prevented by dihydrallazine, suppression of renin release by phenylephrine still occurred. 5. These observations support an inhibitory effect of a non-vascular α-adrenergic mechanism on renin release. It is suggested that the α-receptor mediating this effect is directly related to the renin-producing juxtaglomerular cell.


1975 ◽  
Vol 49 (1) ◽  
pp. 73-76 ◽  
Author(s):  
R. Vandongen

1. The effect of antidiuretic hormone (ADH) on isoprenaline-stimulated renin secretion was examined in the isolated rat kidney perfused with modified Krebs-Ringer saline. 2. Intrarenal infusion of ADH effectively prevented stimulation of renin secretion by isoprenaline whilst increasing renal perfusion pressure. 3. The exclusion of calcium ions from the perfusion medium abolished the vasoconstrictor effect of ADH and attenuated the inhibitory effect of ADH on isoprenaline-stimulated renin secretion. However, significant suppression of renin secretion was still apparent compared with experiments where isoprenaline was infused alone. 4. These observations indicate that ADH inhibits renin secretion and that this is effected by a direct action on the kidney. Although this may be partly mediated by the rise in renal perfusion pressure, an additional direct effect of ADH on the renin-producing cell, which is dependent on the availability of calcium ions, is proposed.


1975 ◽  
Vol 49 (6) ◽  
pp. 609-612
Author(s):  
R. Vandongen ◽  
Dianne M. Greenwood

1. The effect of adrenaline and noradrenaline on renin secretion in the isolated perfused rat kidney was examined. The doses of catecholamines used were such that renal vasoconstriction and therefore increases in renal perfusion pressure were avoided. Under these conditions adrenaline and noradrenaline significantly increased renin secretion rates, compared with control experiments in which no catecholamine was infused. 2. Mean renal perfusion pressure during both adrenaline and noradrenaline infusion paralleled the control study by showing a progressive fall. 3. Administration of phenoxybenzamine did not impair the stimulation of renin secretion by adrenaline whereas this was prevented by racemic propranolol. 4. These observations suggest that catecholamines stimulate renin secretion by an intrarenal effect which is largely independent of changes in renal perfusion pressure. It is postulated that the beta-adrenoceptors mediating renin secretion are an integral component of the renin-producing cell.


1995 ◽  
Vol 269 (1) ◽  
pp. F134-F139 ◽  
Author(s):  
W. H. Beierwaltes

The macula densa is a regulatory site for renin. It contains exclusively the neuronal isoform of nitric oxide synthase (NOS), suggesting NO could stimulate renin secretion through the macula densa pathway. To test whether neuronal NOS mediates renin secretion, renin was stimulated by either the renal baroreceptor or the diuretic furosemide (acting through the macula densa pathway). Renin secretion rate (RSR) was measured in 12 Inactin-anesthetized rats at normal (104 +/- 3 mmHg) and reduced renal perfusion pressure (65 +/- 1 mmHg), before and after selective blockade of the neuronal NOS with 7-nitroindazole (7-NI, 50 mg/kg ip). 7-NI had no effect on basal blood pressure (102 +/- 2 mmHg) or renal blood flow (RBF). Decreasing renal perfusion pressure doubled RSR from 11.8 +/- 3.3 to 22.9 +/- 5.7 ng ANG I.h-1.min-1 (P < 0.01) (ANG I is angiotensin I). Similarly, in 7-NI-treated rats, reduced perfusion doubled RSR from 8.5 +/- 1.8 to 20.5 +/- 6.2 ng ANG I.h-1.min-1 (P < 0.01). Renal hemodynamics and RSR were measured in response to 5 mg/kg iv furosemide in 12 control rats and 11 rats treated with 7-NI. Blocking neuronal NOS did not alter blood pressure (102 +/- 2 mmHg), RBF (5.8 +/- 0.4 ml.min-1.g kidney wt-1), or renal vascular resistance (18.7 +/- 1.4 mmHg.ml-1.min.g kidney wt).(ABSTRACT TRUNCATED AT 250 WORDS)


1997 ◽  
Vol 273 (2) ◽  
pp. F307-F314 ◽  
Author(s):  
R. Loutzenhiser ◽  
L. Chilton ◽  
G. Trottier

An adaptation of the in vitro perfused hydronephrotic rat kidney model allowing in situ measurement of arteriolar membrane potentials is described. At a renal perfusion pressure of 80 mmHg, resting membrane potentials of interlobular arteries (22 +/- 2 microns) and afferent (14 +/- 1 microns) and efferent arterioles (12 +/- 1 microns) were -40 +/- 2 (n = 8), -40 +/- 1 (n = 45), and -38 +/- 2 mV (n = 22), respectively (P = 0.75). Using a dual-pipette system to stabilize the impalement site, we measured afferent and efferent arteriolar membrane potentials during angiotensin II (ANG II)-induced vasoconstriction. ANG II (0.1 nM) reduced afferent arteriolar diameters from 13 +/- 1 to 8 +/- 1 microns (n = 8, P = 0.005) and membrane potentials from -40 +/- 2 to -29 +/- mV (P = 0.012). ANG II elicited a similar vasoconstriction in efferent arterioles, decreasing diameters from 13 +/- 1 to 8 +/- 1 microns (n = 8, P = 0.004), but failed to elicit a significant depolarization (-39 +/- 2 for control; -36 +/- 3 mV for ANG II; P = 0.27). Our findings thus indicate that resting membrane potentials of pre- and postglomerular arterioles are similar and lie near the threshold activation potential for L-type Ca channels. ANG II-induced vasoconstriction appears to be closely coupled to membrane depolarization in the afferent arteriole, whereas mechanical and electrical responses appear to be dissociated in the efferent arteriole.


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.


1979 ◽  
Vol 236 (6) ◽  
pp. F546-F551
Author(s):  
E. H. Blaine ◽  
M. B. Zimmerman

Uninephrectomized ewes were prepared with a renal artery flow probe and catheters were implanted into the renal artery, vein, and ureter. The renal perfusion pressure (RPP) of conscious animals was decreased externally by 13 +/- 3, 21 +/- 3, 31 +/- 3 mmHg over 5 min and returned to control levels over 5 min. Reduction of RPP by 13 and 21 mmHg resulted in prompt increases in renin secretion (RS) which were maximal coincident with the nadir of the downward ramp (delta RS 195 +/- 43 P less than 0.05, and 1,077 +/- 208 ng AI/min, P less than 0.01, respectively). Directly measured renal blood flow (RBF) was not decreased and no measurable change occured in GFR. When RPP was reduced by 31 mmHg, RBF and GFR were decreased and renin secretion rose further (delta RS 1,480 +/- 384 AI/min, P less than 0.05). On the upward pressure ramp, RS fell promptly and was nearly at control levels upon restoration of RPP. It was concluded that renin secretion responds rapidly to alterations in RPP in the autoregulatory range and these changes in renin secretion are unlikely to be mediated by a tubular receptor.


1983 ◽  
Vol 244 (4) ◽  
pp. F418-F424 ◽  
Author(s):  
U. Kopp ◽  
G. F. DiBona

Anesthetized dogs with isolated carotid sinus preparation were used to examine the mechanisms involved in the increase in renin secretion rate produced by carotid baroreceptor reflex renal nerve stimulation (RNS) at constant renal perfusion pressure. Lowering carotid sinus pressure by 41 +/- 5 mmHg for 10 min increased mean arterial pressure and heart rate, caused no or minimal renal hemodynamic changes, decreased urinary sodium excretion, and increased renin secretion rate. Metoprolol, a beta 1-adrenoceptor antagonist, given in the renal artery, did not affect the decrease in urinary sodium excretion but attenuated the increase in renin secretion rate, from 1,764 +/- 525 to 412 +/- 126 ng/min (70 +/- 8%). Indomethacin or meclofenamate, prostaglandin synthesis inhibitors, did not affect the decrease in urinary sodium excretion but attenuated the increase in renin secretion rate, from 1,523 +/- 416 to 866 +/- 413 ng/min (51 +/- 18%). Addition of metoprolol to indomethacin-pretreated dogs attenuated the increase in renin secretion rate from 833 +/- 327 to 94 +/- 60 ng/min (86 +/- 10%). These results indicate that reflex RNS at constant renal perfusion pressure results in an increase in renin secretion rate that is largely mediated by renal beta 1-adrenoceptors and is partly dependent on intact renal prostaglandin synthesis. The beta 1-adrenoceptor-mediated increase in renin secretion rate is independent of and not in series with renal prostaglandins.


1988 ◽  
Vol 255 (3) ◽  
pp. F391-F396 ◽  
Author(s):  
J. D. Firth ◽  
A. E. Raine ◽  
J. G. Ledingham

The effect of alteration in renal perfusion pressure on the response of the isolated perfused rat kidney to concentrations of alpha-human atrial natriuretic peptide (ANP) within the pathophysiological range has been examined. At a perfusion pressure of 90 mmHg ANP concentrations of 50, 200, and 1,000 pmol/l were without effect on any parameter tested. At a perfusion pressure of 130 mmHg 50 pmol/l ANP produced an increase of 3.13 +/- 0.68 mumol/min in sodium excretion (UNa V), compared with a fall of 0.33 +/- 1.04 mumol/min in controls (P less than 0.02); fractional excretion of sodium (FENa) rose by 1.45 +/- 0.36% vs. -0.12 +/- 0.47% (P less than 0.05); glomerular filtration rate (GFR) was unchanged. At 200 and 1,000 pmol/l larger changes in UNa V and FENa were seen; only at 1,000 pmol/l was a significant effect on GFR observed. In contrast, frusemide (furosemide) at concentrations of 10 and 100 mumol/l was natriuretic at both 90 and 130 mmHg, with lesser absolute but greater proportional changes being seen at the lower pressure. It was concluded 1) the response of the isolated kidney to ANP is critically dependent on perfusion pressure, 2) at elevated levels of perfusion pressure the isolated kidney can respond to levels of ANP within the upper physiological and pathophysiological range.


1976 ◽  
Vol 51 (s3) ◽  
pp. 101s-104s
Author(s):  
R. Vandongen ◽  
Dianne M. Greenwood

1. The effect of diazoxide (17·3 μmol min—1 g—1) and frusemide (0·12 μmol min—1 g—1) on renin secretion was examined in the isolated perfused rat kidney. These substances are potential renal vasodilators with opposite effects on urine sodium excretion. 2. Both agents significantly increased renin secretion rate above control values. In the case of frusemide this was not altered by ureteric occlusion and presumed absence of urine flow. 3. Mean renal perfusion pressure decreased to the same extent with diazoxide and frusemide infusion as in the control experiments and no additional vasodilatory effect was observed on the basis of changes in flow rate of perfusate. 4. These observations identify an intrarenal site of action for diazoxide and frusemide on renin secretion. The apparent independence of this stimulatory action on renal vasodilatation and urine flow suggests a direct effect on the renin-producing cell.


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