title: Effects of 5-hydroxytryptamine on membrane potential, contractility, accumulation of cyclic AMP, and Ca2+ movements in anterior aorta and ventricle of Aplysia.
abstract: Effects of 5-hydroxytryptamine (serotonin; 5-HT) on the anterior aorta and ventricle muscle of the marine gastropod Aplysia are characterized. Bath-applied 5-HT depolarizes muscle fibers and causes tension increases in both the anterior aorta and ventricle above ca. 10(-9) M. Iontophoretically applied 5-HT caused localized depolarizations of anterior aorta muscle fibers. 5-HT increases the levels of adenosine-3',5'-cyclic monophosphate (cAMP) markedly in the anterior aorta of A. kurodai and A. californica and in the ventricle of A. kurodai. Effects of 5-HT on the contractility of and cAMP synthesis in the anterior aorta and ventricle are both blocked by methysergide. 5-HT and cAMP analogs stimulate 45Ca2+ efflux from the ventricle, implying that the effects of cAMP on contractility involve intracellular Ca2+ movements.
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D001048:Aplysia / Q000502:physiology*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D006321:Heart / Q000187:drug effects*; D006352:Heart Ventricles; D007478:Iontophoresis; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects*; D009206:Myocardium / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D010726:Phosphodiesterase Inhibitors; D012701:Serotonin; D000242:Cyclic AMP; D002118:Calcium