EXPRESSION AND REGULATION OF GALANIN-R2 RECEPTORS IN RAT PRIMARY SENSORY NEURONS - EFFECT OF AXOTOMY AND INFLAMMATION

Using in situ hybridization, we studied galanin-Re receptor (GAL-R2-R) mRNA in rat lumbar 5 dorsal root ganglia (DRGs) at different time poi nts after peripheral tissue inflammation and sciatic nerve transection (axotomy). About 25% of all normal DRG neuron profiles were GAL-R2-R mRNA-positive, and the majority was of the small type. In normal DRGs GAL-R2-R mRNA often (approximate to 80%) colocalized with CGRP mRNA an d sometimes (approximate to 20%) with GAL-R1-R mRNA. There was a stron g increase in the number and labeling intensity of GAL-R2-R mRNA-posit ive neuron profiles after peripheral tissue inflammation with a peak a t 3 days, as well as a long-lasting decrease after axotomy. These resu lts, together with the previously shown regulation of GAL and the GAL- R1-R, suggest that GALergic mechanisms participate in complex adaptive responses in DRGs after inflammation and nerve injury. (C) 1997 Elsev ier Science Ireland Ltd.