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

Peripheral administration of amylin (40 mu g 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 DA(2) antagonists. Pretreatment with SCH 23390 (0.5-4 mg kg(-1) s.c.), a DA(1) 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 DA(1) and DA(2) receptor subtypes. (C) 1998 The Italian Pharmacology Society.