Decreases of action potential amplitudes, in sodium-free and calcium-free conditions, of identifiable giant neurones of an African giant snail ( Achatina fulica férussac)—II. The visceral ganglion

Abstract

1. 1. Decreases of the action potential amplitudes in sodium-free and calcium-free states were studied with respect to the six giant neurons, VIN (visceral intermittently firing neuron), FAN (frequently autoactive neuron), d-VLN (dorsal-visceral large neuron), 1-VMN (left-visceral multiple spike neuron), v-VLN (ventral-visceral large neuron) and v-l-VOrN (ventral-left-visceral oral neuron), identified hi the right parietal ganglion of an African giant snail ( Achatina fulica Férussac). 2. 2. Action potential amplitudes of all the neurons tested decreased in both sodium-free and calcium-free conditions. However, the ratios of their decreases varied according to the neurons tested. 3. 3. Of the neurons tested, the action potential of FAN was considered to be more dependent on sodium, those of 1-VMN and v-VLN were dependent comparably on both sodium and calcium, and those of VIN, d-VLN and v-l-VOrN were more dependent on calcium.