Predictable and unpredictable shock stimulates gastric contractility and causes mucosal injury in rats.

The effects of tailshock on gastric contractility and lesions were investigated in rats exposed to 100 1-mA tailshocks while confined inside plastic tubes. A light preceded each shock in one group and was randomly presented with respect to shock in the other. Contractility of the corpus of the stomach was measured by means of chronically implanted extraluminal force transducers. Contractility was measured in 10-min blocks and analyzed by computer. Signaled (n?=?13) and unsignaled (n?=?17) shock stimulated high-amplitude gastric contractions in fasted rats, which continued for 2 hr after the shock session. Cumulative contractile activity (1.5-hr shock plus 2-hr rest) in shocked animals was twice that in restrained and unrestrained control animals (n?=?19, p?