ACTION AND MECHANISM OF ACTION OF VERATRINE ON RENIN SECRETION FROM RAT-KIDNEY SLICES

Publisher Website
Google Scholar
Abstract
Norepinephrine released from the renal nerves stimulates the secretion of renin by a .beta.-adrenergic mechanism. The effects of renin secretion of veratrine, which depolarizes nerve terminals and thereby causes transmitter release, were studied. The rat renal cortical slice preparation was used. Veratrine (10-200 .mu.M) stimulated renin secretion in a concentration-dependent manner. Veratrine-stimulated secretion was antagonized by timolol (0.9 and 9.0 .mu.M) and by tetrodoxin (0.5 and 5.0 .mu.M), a Na channel blocker. Neither drug completely abolished the stimulatory effect of veratrine. Veratrine stimulated renin secretion in slices prepared from previously denervated kidneys; this response was not antagonized by timolol. Veratrine evidently stimulates renin secretion by at least 2 mechanisms. One component probably consists of veratrine-induced depolarization of renal nerve terminals, release of norepinephrine and activation of juxtaglomerular cell .beta. adrenergic receptors; the other component appears to be independent of nerve terminals in the preparation. The tetrodotoxin-sensitive component of veratrine-stimulated renin secretion in this preparation is evidently an in vitro model of renal nerve-stimulated renin secretion; it should be useful in investigating substances which affect renin secretion by presynapatic modulation of transmitter release.