Localization of preprogalanin mRNA in rat brain: in situ hybridization study with a synthetic oligonucleotide probe.

Galanin is a peptide containing 29 amino acid residues that is present in both the central and peripheral nervous systems. Galanin has multiple putative biological functions including regulation of hormone release, stimulation of feeding behaviour, and effects on blood pressure. This study examined the distribution of neurones expressing preprogalanin mRNA in the rat brain by in situ hybridization of a specific 35S-labelled oligonucleotide. Preprogalanin mRNA was detected in several regions of brain, with high concentrations in the paraventricular, periventricular, supraoptic, dorsomedial and arcuate nuclei of the hypothalamus; the locus coeruleus and dorsal raphe nucleus in the pons; and the nucleus tractus solitarii and ventrolateral reticular nucleus in the medulla. These findings are consistent with studies of the cellular localization of galanin-like immunoreactivity in rat brain, and further suggest the involvement of galanin in the regulation of several functions ranging from water balance to blood pressure control.