LEMAKALIM, A POTASSIUM CHANNEL AGONIST, REVERSES ELECTROPHYSIOLOGICALIMPAIRMENTS INDUCED BY A LARGE DOSE OF BUPIVACAINE IN ANESTHETIZED DOGS

We have examined the ability of lemakalim to correct bupivacaine-induc ed cardiac electrophysiological impairment in an experimental electrop hysiological model in closed-chest dogs. Two groups (n = 6) of pentoba rbitone-anaesthetized dogs were given atropine 0.2 mg kg-1 i.v., and b upivacaine 4 mg kg-1 i.v. over 10 s. Group 2 received also lemakalim 0 . 03 mg kg-1 i. v. Bupivacaine induced bradycardia, prolonged PR and H is-ventricle (HV) intervals, QRS duration, QTc and JTc intervals, decr eased left ventricular (LV) dP/dt max and increased LV end- diastolic pressure. Lemakalim reversed bupivacaine-induced PR, HV, QRS, QTc and JTc prolongation, and did not worsen bupivacaine-induced bradycardia a nd haemodynamic depression. We conclude that lemakalim can antagonize the main deleterious electrophysiological effects induced by a large d ose of bupivacaine in anaesthetized dogs.