The action of anticonvulsant drugs on the firing of locus coeruleus neurons: selective, activating effect of carbamazepine.

The action of various doses of intraperitoneally administered carbamazepine, ethosuximide, Na-valproate, phenobarbital and diphenylhydantoin on the neuronal firing rate of presumed noradrenergic neurons of the locus coeruleus was investigated in the anaesthetized rat. Carbamazepine was the only compound which produced a statistically significant, dose-dependent activation of these neurons. The other anticonvulsant drugs caused a small but non significant reduction in locus coeruleus cell firing. It is concluded that this brain nucleus is not a main target of anticonvulsant drugs.