Figure 5: Possible mechanisms involved in potentiation of GSIS by A3AR. This receptor possibly through elevation of intracellular Ca2+ potentiates GSIS. This effect was observed at low concentrations of Cl-IBMECA (> 1 μM). It is possible that at higher concentrations (< 10 μM) cAMP levels decrease extensively and limit potentiation of GSIS. GSIS, Glucose-stimulated insulin secretion; A3AR, A3 adenosine receptor ; Cl-IBMECA, A3AR agonist; AC, adenylyl cyclase.