Neuronal supersensitivity to acetylcholine induced by kindling in the rat hippocampus.

Kindling is an experimental model of epilepsy in which periodic brain stimulation induces the progressive development of electrical and behavioral seizures. A kindling-induced electrical seizure (afterdischarge) in the rat hippocampus produces prolonged neuronal supersensitivity to microiontophoretically applied acetylcholine after a latency of 40 to 60 minutes. Neuronal acetylcholine supersensitivity is correlated with the further progression of kindling. A larger hippocampal after-discharge is elicited by a subsequent kindling stimulus delivered in the presence of acetylcholine supersensitivity, but not by one delivered before the onset of the supersensitivity. The results suggest that alteration of synaptic sensitivity to acetylcholine may contribute to kindling and epileptogenesis.