Histamine stimulates renin release from the isolated perfused rat kidney.

The renal effects of histamine, histamine receptor agonists and antagonists were studied in the isolated rat kidney, which was perfused with a synthetic medium at constant perfusion pressure in a single pass system. Histamine induced a concentration-dependent increase of renin release ranging from a two-fold increase at 0.5 microM to a four-fold increase at 10 microM. No change in renal vascular resistance, glomerular filtration rate and sodium excretion occurred. Histamine-H2-antagonists (ranitidine and cimetidine) were more effective to block the response to histamine than was the histamine H1-antagonist diphenhydramine. Histamine-H2-agonists (impromidine and dimaprit, 2.5 microM each) were potent stimulators of renin release, their effect was blunted by H2-antagonists. The histamine-H1-agonist pyridyl-2-ethylamine had a low stimulatory activity at 10 microM final concentration, which may reflect partial H2-agonistic effects. It is concluded that histamine stimulates renin release via H2-receptor activation.