Vagal stimulation-induced gastric acid secretion in the anesthetized rat

The dynamics of gastric acid secretion induced by electrical stimulation of the cervical vagus in the anesthetized rat were investigated using a continuous collection-titration system permitting high temporal resolution. Stimulation with pulse rates of 2 or 4 impulses/s (pps) produced maximal gastric acid responses with small cardiovascular effects. With continuous stimulation, secretion was sustained for at least 1 h. Frequency-response profiles suggested that the parietal cells are innervated predominantly by fine-caliber C-fibers. Continuous stimulation was 3 times as effective as stimulation in bursts of higher frequencies. The minimal latency for the onset of secretion was 2.6 min at 4 pps, however, one- and two-min stimulations still produced proportionate but delayed secretory responses. It is concluded that, with low frequency cervical vagus stimulation, the rat stomach preparation described and employed in the present experiment is a useful model for further studies on the interaction of neural and humoral factors on gastric acid secretion.