THE EFFECTS OF CERTAIN NEUROHUMORS AND OF OTHER DRUGS ON THE VENTRICLE AND RADULA PROTRACTOR OF BUSYCON CANALICULATUM AND ON THE VENTRICLE OF STROMBUS GIGAS

Abstract

1. The hearts of Busycon canaliculatum and Strombus gigas were found to respond to applied neurohumors as do the myogenic hearts of other gastropods. Acetyicholine was cardio-inhibitory, and 5-hydroxytryptamine was cardio-acceleratory, in concentrations low enough to suggest that they might be the normal regulatory neurohumors.2. The Busycon canaliculatum radula protractor was contracted by acetylcholine, and could then be relaxed rhythmically by 5-hydroxytryptamine, tryptamine, and adrenalin, all of which raise the tonus of the ventricle.