Brainstem evoked response to dorsal vagal gastric input from the proximal stomach

Unitary responses to electrical stimulation of gastric vagal fibers, that serve the proximal stomach and join the dorsal vagal trunk, were bilaterally distributed in nucleus tractus solitarus (NTS) in the brainstem of the cat. The vagally activated brainstem responses consisted of single or multiple spikes with a mean latency of 281 (SD ± 43 ms) which translated into a conduction velocity of < 1 m/s. Ninety-eight percent of the responses were orthodromic in character. Twenty percent of the gastric vagally-evoked brainstem unitary responses received input from both the dorsal and ventral vagal trunks. Excitatory and inhibitory convergent interactions were observed in the brainstem units receiving gastric input from both the dorsal and ventral vagal trunks.