Modulation of the Rat Adrenal Medulla Norepinephrine Secretion in a Sodium-Free Medium by Atrial Natriuretic Factor

VATTA MS; PAPOUCHADO ML; BIANCIOTTI LG; FERNADEZ BE

PEPTIDES

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 1994 vol. 15 p. 709 - 712

0196-9781

The effects of atrial natriuretic factor (ANF) on [3H]norepinephrine ([3H]NE) release evoked by a sodium-free medium (SFM) were studied. Experiments were performed in rat adrenal medulla slices incubated in vitro. Results showed that [3H]NE release evoked by the omission of Na + was decreased by 10 nM ANF. In addition, when the Ca 2÷ was omitted from the SFM, NE output was partially diminished. Nevertheless, if ANF was added to SFM/Ca2+-free medium (CFM), NE secretion showed no modifications compared with SFM/CFM. Present results raise the hypothesis that two mechanisms could be involved in NE output evoked by a SFM in the rat adrenal medulla: one independent of and the other dependent on the extracellular calcium. Moreover, ANF only diminished NE secretion evoked by SFM dependent on extracellular calcium and did not modify calcium-independent NE release.