Expression of GAL mRNA in rat hypothalamus: effect of frontal deafferentation and colchicine treatment.

The expression of galanin (GAL) mRNA was determined by in situ hybridization after frontal deafferentation and colchicine treatment in the rat hypothalamus. Frontal deafferentation significantly increased the signal in the paraventricular nucleus (PVN), the supraoptic nucleus (SON), and dorsomedial nucleus (DMN). Colchicine treatment induced a diffuse enhancement of GAL mRNA in hypothalamic nuclei. When the two treatments were combined there was an additivity of GAL mRNA expression in the previous hypothalamic nuclei and also in the arcuate nucleus (AN), where the single treatments did not modify the signal. These results suggest the regulation of GAL mRNA expression mediated by a multineuronal pathway, separate from the colchicine-induced GAL mRNA increase.