EFFECTS AND RECEPTOR MECHANISM OF ADENOSINE ON K~+, Ca~(2+) CHANNELS IN ATRIAL CELLS

Using patch clamp whole cell recording, we investigated the effects of Ado and DPCPXon IK, Ik.(rail)and L-ICh of enzymatic atrial myocytes from guinea pig heart- The resu1ts indicated: 3 mol/L Ado could increase IK and lk.(rail) and reduced both the fast and slow time constants of Ik(tail) (P 0. 0l )Meanwhile, Ado decreased L-Ica and prolonged its activation and inactivation time constants. But Adohad no effects on threshold, reversal potentials, maximal peak v0ltage, time-dependent and voltage-dependent of IK and L-(Ica) These acti0ns could be eliminated by DPCPX. The results suggested the effectsof Ado on IK t L-ICa in atrial cells were mediated by A, receptor.