RESUMO
The role of the atrial natriuretic peptide on calcium channel mechanisms involved in catecholamine release was studied in the perfused bovine adrenal medulla. The atrial natriuretic peptide (1 nM and 10 nM) did not modify the spontaneous release of catecholamines. Ten nM of atrial natriuretic peptide decreased the output of catecholamines induced by acetylcholine, KCl-depolarizing solutions and angiotensin II. It was ineffective to modify the catecholamine release when calcium channels were blocked or in the presence of calcium-free media. Moreover, the deprivation of the ion calcium in the media decreased the catecholamine release induced by KCl to a lowest level, despite the presence of atrial natriuretic peptide in the perfusate. In conclusion, atrial natriuretic peptide inhibited the induced secretion of catecholamines in the bovine adrenal medulla and interfered as a partial blocker with calcium-dependent mechanisms.
