Neurobiology of the Gorgonian Coelenterates, Muricea Californica and Lophogorgia Chilensis

Abstract

ABSTRACT Electrical or mechanical stimulation of Muricea californica or Lopho- gorgia chilensis colonies resulted in withdrawal of polyps in the immediate vicinity of the stimulation point. Additional stimulation did not result in further spread of polyp retraction. Electrical activity was recorded from a colonial conduction system not restricted to the area of polyp withdrawal. Conduction velocity in this conduction system decreased with increasing stimulus number and distance from the stimulation point. Polyp withdrawal in Muricea occurred concomitantly with a burst of facilitating electrical impulses. The withdrawal burst was always preceded by impulses of the colonial conduction system. The pattern of colonial behaviour in gorgonians depends upon the conduction properties of the colonial conduction system, the conduction system(s) of each individual polyp, and the pathways connecting the two. Polyp tentacles bend to the oral disk when presented with liver extract. A burst of electrical impulses was recorded from Muricea polyps during chemical stimulation. These bursts exhibited apparent adaptation and presumably represent muscle potentials resulting from chemoreceptor activation.