Attempt to antagonize the stimulatory effect of ATP on insulin secretion

Abstract

An attempt was made to antagonize the stimulatory effect of ATP on insulin secretion from the isolated perfused rat pancreas. The insulin secretory effect of ATP does not seem to be mediated by cholinergicc or β-adrenergic receptors since neither atropine 0.3 μmol/1 nor propranolol 1 μmol/1 had any antagonistic action on insulin secretion induced by ATP (16.5 μmol/1). Theophylline (50 μmol/1) did not antagonize the insulin secretion evoked by ATP (16.5 μmol/1). Apamin (10 nmol/1) was also without antagonistic action. 2-2′Pyridylisatogen tosylate (5 μmol/1) had no effect on insulin secretion induced by glucose (8.33 mmol/1) or acetylcholine (0.5 μmol/1 and 0.1 μmol/1) but inhibited the insulin secretory effect of ATP (16.5 μmol/1). Thus, the antagonism of 2-2′pyridylisatogen for ATP seems selective. We conclude that a purinoceptor of the P 2-type is likely to be present on the B-cell of the rat pancreas.