[Excitatory and inhibitory vagal actions on the motility of normal rabbit stomach]

Electrical vagal nerve stimulation (10-20 V, 0.2-5 msec, 1-86 Hz) was carried out at cervical level in nembutal-urethane anestetized rabbits. The aim of the research was to selectively activate (0.2 msec) "low" excitatory, and (5 msec) "high" inhibitory efferent vagal nerve fibers supplying the stomach. In the intact stomach an increasing motor effect was evoked between 1 and 16 Hz. An inhibitory motor effect became, instead, evident at higher frequencies of stimulation (16-86 Hz) In atropinized animals excitatory motor effects were blocked. The inhibitory effects were instead still present and they were not affected by guanethidine. These results suggest a non-cholinergic, non-adrenergic mechanism for the vagal inhibitory control of gastric motility in rabbit.