Effect of AF64A, a cholinergic neurotoxin, on footshock stimulation-induced locus coeruleus excitation in rats

We studied the effect of ethylcholine mustard aziridinium ion (AF64A), a ch olinergic neurotoxin, on the footshock stimulation (FS)-induced excitation of the locus coeruleus (LC) neurons in rats. The FS-evoked LC excitation wa s significantly reduced in AF64A-treated rats, in comparison with normal ra ts. In particular, the early component of LC excitation was less pronounced . The number of choline acetyltransferase immunoreactive neurons in the sep tal complex was significantly lower than those in normal rats, except for i n the ventral subgroup. These findings suggest that the cholinergic neuron system is involved in the early component of LC excitation in rats. (C) 200 1 Elsevier Science Ireland Ltd. All rights reserved.