Opiate withdrawal increases glutamate and aspartate efflux in the locus coeruleus: an in vivo microdialysis study.

Electrophysiological studies suggest that an increase in excitatory amino acid release may occur in the locus coeruleus during opiate withdrawal. The present study examined directly by microdialysis in anesthetized rats the effect of naltrexone-precipitated opiate withdrawal on the efflux of excitatory amino acids in the locus coeruleus. A withdrawal-induced increase in glutamate and aspartate efflux was found when the microdialysis probe was located in the core of the locus coeruleus; no increase was seen in adjacent regions.