The excitatory and inhibitory innervation of the stomachs of the domestic fowl.

The role of the autonomic nerve on the gastric motility of the domestic fowl has been investigated by Nolf (1), Ihnen (2) and Hassan (3). Nolf has reported that both excitatory and inhibitory fibres are included in the vagus and also in the sympathetic nerve to the proventriculus and gizzard. However, there is little detailed study on the mechanism which causes excitatory and inhibitory responses of the fowl's stomach to stimulation of these nerves. In mammalians, the inhibitory response of the stomach caused by vagal stimulation was distinguished from that caused by sympathetic stimulation and was attributed to a non-adrenergic inhibitory nerve mechanism (4-8). It was also reported that the excita tory cholinergic fibres in addition to the inhibitory adrenergic one are contained in the sympathetic nerve to the stomach (9-11). Recent electrophysiological studies have shown that the smooth muscle cells of the avian gizzard may be affected by excitatory cholinergic nerve fibres and by non-adrenergic inhibitory nerve fibres (12, 13). The present experiment is concerned with the nature of the excitatory and inhibitory responses to stimulation of the vagus and the sympathetic nerves to the crop, proventriculus and gizzard in the domestic fowl. The main purpose of this work is to examine whether the relaxation of the stomach caused by stimulation of these nerves is adrenergic in origin or not.