Inhibition of restraint stress by systemic (Asu1,7) eel-calcitonin.

The effects of different doses of (Asu1,7) eel-calcitonin, iv injected, on gastric secretion were studied in conscious rats with pyloric occlusion. Moreover, we evaluated the activity of this analogue on gastric ulcer formation by restraint stress. It was found that 2.5 or 5 Ul/kg (Asu1,7) eel-calcitonin decreased gastric acid secretion and inhibited the development of stress-induced ulcers in rats. In the isolated rat stomach the peptide at the concentrations of 1 nM to 1 microM did not modify acetylcholine, histamine or 5-hydroxytriptamine-induced contractions. These results suggest that this peripheral activity of (Asu1,7) eel-calcitonin does not involve a direct interference with cholinergic, histaminergic or serotonergic pathways at gastric level.