REDUCED PROCONVULSANT ACTIVITY OF CAFFEINE IN RATS AFTER A SERIES OF ELECTROCONVULSIVE SEIZURES

A variety of neurotransmitter receptor changes occur after a course of electroconvulsive seizures (ECS) in rats, including an increased dens ity of adenosine A(1) sites. Adenosine antagonism has been related to the proconvulsant action of methylxanthines such as caffeine. We deter mined tonic-clonic seizure duration in rats given ECS with caffeine (0 -175 mg/kg, IP) after a course of one or six daily ECS. A single day o f ECS did not affect the dose-dependent proconvulsant action of caffei ne. After six daily ECS, the proconvulsant action of caffeine was redu ced. After nine daily ECS, an A(1) antagonist (8-cyclopentyl-1,3-dipro pylxanthine) and an A(2A) antagonist (1-allyl-3,7-dimethyl-8-p-sulfoph enylxanthine) showed reduced proconvulsant activity. The results sugge st that the reduced proconvulsant action of caffeine after chronic ECS depends on adenosine antagonism.