Involvement of DA1 and DA2 receptors in the gastroprotective activity of amylin in the rat.

Peripheral administration of amylin (40 microg kg-1) exerts gastroprotective effects in the reserpine-induced gastric lesions in the rat. This activity is decreased by pretreatment (30 min before) with (-)-sulpiride (0.1 mg kg-1 s.c.) or domperidone (0.1-2.5 mg kg-1 per os), dopamine DA2 antagonists. Pretreatment with SCH 23390 (0.5-4 mg kg-1 s.c.), a DA1 antagonist, at the maximal dose used, also significantly decreased the gastroprotective activity of the peptide. Amylin does not exert any gastroprotective effect in indomethacin-pretreated rats (7.5 mg kg-1 s.c., 30 min before), as well as in the aspirin-induced ulcer test (200 mg kg-1 per os at the time of amylin administration). Our data confirm that the gastroprotective effect of amylin in reserpine-induced gastric lesions involves, at least in part, the dopaminergic transmission, interfering with both the DA1 and DA2 receptor subtypes.