Susceptibility of stress-induced ulcer by restraint water immersion (RWI) was examined in Wistar Kyoto rats (WKY), spontaneously hypertensive rats (SHR) and stroke-prone spontaneously hypertensive rats (SHRSP).

Ulcer formation was slight in SHR, and very slight in SHRSP.

The ulcer index and blood pressure showed a significant inverse correlation (P < 0.001).

Acid secretion was lowest in SHRSP, and hypergastrinemia was present in SHRSP.

Gastric motility was suppressed during RWI in SHR and SHRSP.

The noradrenaline content of the gastric mucosa and muscle layer was significantly greater in these hypertensive strains, and histologically noradrenergic innervation in the mucosa was also denser in SHRSP and SHR.

Choline acetyltransferase activity in the stomach was significantly lower in SHR and SHRSP than WKY (P < 0.01).

These findings suggest that susceptibility of stress-induced ulcer is inversely correlated with systemic blood pressure and that the alteration of autonomic nervous function contributes to inhibition of stress ulcers by suppressing acid secretion and motility in the hereditary hypertensive rats.