Decreased activity of locus coeruleus neurons in the rat after DSP-4 treatment

The activity of noradrenergic neurons of the rat locus coeruleus was investigated at 10 and 50 days after the administration of DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzyl-amine), a selective noradrenergic neurotoxin. The mean neuronal firing rate in control animals was 2.4 Hz. In contrast, DSP-4 animals had lower rates of 1.2 Hz at 10 days and 1.7 Hz at 50 days. Histological examinations revealed no morphological changes of locus coeruleus cell bodies at either the 10- or 50-day time points. These results suggest that DSP-4 can impair neuronal activity of the locus coeruleus without altering the structural appearance of locus coeruleus perikarya.