[Stimulatory effect of vasoactive intestinal peptide microinjected into dorsal vagal complex on gastric acid...

Effects of microinjection of vasoactive intestinal peptide (VIP) into cisterna magna, dorsal vagal complex (dorsal motor nucleus of the vagus, nucleus tractus solitarius and area postrema) and spinal subarachnoid space on gastric acid secretion (GAS) were observed in Ghosh-Schild's rats. The results were as follows: (1) VIP (10 micrograms) injected into the cisterna magna significantly stimulated GAS reaching a peak at 60-100 min after injection and lasting for more than 2.5 h. (2) The increase could be completely abolished by bilateral subdiaphragmatic vagotomy. (3) 20-30 min after injection of 1 microgram VIP into the dorsal vagal complex could also induce a peak increase in GAS. (4) Intrathecal injection of VIP (10 micrograms) did not affect GAS. The results indicate that central VIP-stimulated GAS is mediated by vagus from a special region of dorsal vagal complex.