Direct evidence for central action of PCPGABA to stimulate gastric acid secretion by intracisternal injection.

PCPGABA, injected into the cisterna magna, significantly stimulated gastric acid secretion in the perfused rat stomach preparation. This secretagogue action was dose-dependent (0.5-2 micrograms/rat). The peak response occurred within 60 min and lasted up to 100 min. The secretagogue action by PCPGABA was completely reduced by truncal vagotomy. Intracisternal injection of 5-aminovaleric acid, a GABAB-receptor antagonist, did not alter basal gastric acid output, and it also failed to antagonize the acid secretory response to intracisternal PCPGABA. These results demonstrate that intracisternal PCPGABA caused hypersecretion of acid through vagal dependent mechanisms partially independent of GABAB-receptors.