1990 Volume 21 Issue 1 Pages 21-29
Although mechanical stimuli such as atrial muscle stretch induced by atrial pressure increase or volume overload release atrial natriuretic polypeptide (ANP), transmembrane and intracellular mechanisms of production and release of ANP are not yet clear. To define biochemical mechanisms of regulation of ANP release, the direct effects of biochemical stimuli, such as acetylcholine, isoproterenol, methoxamine, vasopressin and high osmolalities, were evaluated on isolated adult rat atrial myocytes maintained on tissue culture. ANP release from adult rat atrial myocytes was enhanced by acetylcholine or methoxamine with reciprocal intracellular ANP reduction. Block of muscarinic receptors by atropine and of alpha-1 adrenergic receptors by bunazosin attenuated transmembrane ANP release. These results suggest that phosphatidylinositol response, which is a common pathway for muscarinic and alpha-1 adrenergic receptor stimulation, may play an important role to regulate ANP release.
