Increased activity of choline acetyltransferase and acetylcholinesterase in actively epileptic human cerebral cortex.

We measured the activities of the cholinergic marker synthetic and catabolic enzymes choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) in surgical specimens obtained from 38 patients immediately following anterior temporal lobectomy for intractable epilepsy. Samples from patients with actively spiking lateral temporal cortex were compared to non-spiking lateral temporal cortex obtained from patients in whom the epileptic discharges were confined to the hippocampus. Mean activities of ChAT and AChE were increased by 25% (P less than 0.01) and 30% (P less than 0.025) respectively in the spiking vs. non-spiking cortex. We suggest that the above-normal activity of these cholinergic marker enzymes may reflect sprouting of cholinergic nerve terminals in spontaneously spiking cortex of some patients and/or increased acetylcholine metabolism secondary to the stimulatory effect of the ongoing epileptic discharge.