DA1 receptor-mediated renin release from isolated rat glomeruli.

The present study was performed in order to examine the effects of dopamine (DA) on renin release and to clarify which subtype of DA receptor, DA1 or DA2 contributes to renin release. Male Wistar rats aged seven weeks were used. Glomeruli were isolated by the modified Beierwaltes' sieving method and were transferred to a sealed chamber and superfused with Krebs-Ringer solution. In the first experiment, the changes in renin release induced by DA and the effects of a non-selective DA antagonist, haloperidol and a beta antagonist, propranolol on DA-induced renin release were examined. In the second experiment, the effect of a DA2 receptors antagonist, spiperone and of a DA1 receptor antagonist, SCH-23390 on renin release were investigated. Basal levels of renin release were 2.46 +/- 0.36 ng ATI/h/10(4) glomeruli (mean +/- SEM). DA caused a dose-dependent increase in renin release. The renin release induced by DA was inhibited by haloperidol but not by propranolol. The maximum level of renin release induced by 10(-5)M DA was 4.13 +/- 0.63 ng ATI/h/10(4) glomeruli. SCH-23390 at 10(-5)M caused significant suppression of DA-induced renin (p < 0.05). In contrast, 10(-5)M spiperone failed to suppress DA-induced renin release. These results suggest that DA induced renin release from isolated glomeruli through the DA1 receptors.