...) and 27 min after addition of Mn 2+ (RP = —67 mV). Beirão & Sorenson (1986) described the occurrence of spike-like and cardiac like action potentials in the clam mantle, and proposed that the latter were made up of two distinct components: an earlier, faster one that originates the spike...

... current across the apical membrane, so we conclude that the basolateral membrane is the excitable one. * Present address: Instituto de Biolósica, UFRJ, Ilha do Fundāo, 21910 Rio de Janeiro, RJ, Brazil. 26 9 1985 © 1986 by Company of Biologists 1986 clam mantle epithelial...