An A2-purinoceptor Agonist, NECA, Potentiates Acetylcholine-induced Glucagon Secretion

The effect of a stable structural analogue of adenosine, 5'-N-ethylcarboxamidoadenosine (NECA), was studied on glucagon secretion induced by acetylcholine (ACh) in the isolated perfused pancreas of the newborn dog. The perfusion solution contained a physiological concentration of glucose (4.2 mM). In the first set of experiments, ACh (0.5 microM) infused alone for 10 min induced a significant rise of glucagon secretion (370 +/- 98%, 4 min after the beginning of infusion). In the second set, NECA (2.2 nM) infused 10 min before ACh administration, had no effect per se, but considerably increased the response to ACh (929 +/- 262% of basal value within 3 min). So, the more specific A2 purinoceptor agonist, NECA, potentiated glucagon secretion induced by the cholinoceptor agonist, ACh.