Neuronal hypersensitivity to acetylcholinesterase inhibitors induced by a kindling stimulus in the rabbit brain

Kindling has been studied primarily with electrical stimuli applied to subcortical structures in the limbic system. Several recent pharmacological studies have implicated muscarinic cholinergic synapses in the genesis of limbic epilepsy. The present investigation was designed to test the hypothesis that cholinergic neurons may constitute a critical element in the neuronal circuitry of kindling. Chemitrodes implanted in rabbit brains enabled both electrical and chemical stimulations of limbic structures. The results indicate that only few electrical kindling-stimuli produce prolonged hypersensitivity to intracerebrally injected physostigmine. A subsequent electrical stimulus continues the kindling progression. The cholinergic supersensitivity persisted for a long time and was suppressed only by intramuscular injections of scopolamine.