Differential effects of agents enhancing purinergic transmission upon the antielectroshock efficacy of carbamazepine, diphenylhydantoin, diazepam, phenobarbital, and valproate in mice
Following the intraperitoneal administration of the adenosine analogues, 2-chloro-adenosine (1-4 mg/kg) or 5'-N-ethylcarboxamidoadenosine (NECA; 0.01-0.5 mg/kg) to audiogenic DBA/2 mice, there is a potent protection against sound-induced seizures and a simultaneous large (2-5 degrees) reduction in body temperature. The anticonvulsant potency of the adenosine analogues is almost completely abolished by pretreatment with methylxanthines or warming the mice to prevent the adenosine-induced temperature decrease. Adenosine (0.01-1 mM), 2-chloro-adenosine (0.1-1 mM) and NECA (0.1 mM) also significantly inhibit potassium-evoked release of 3H-D-aspartate from rat hippocampal slices. This inhibition is not affected by theophylline (1 mM).