Increase in galanin and neuropeptide Y mRNA in locus coeruleus following acute reserpine treatment.

Galanin and neuropeptide Y are known to coexist with noradrenaline in neurones of the locus coeruleus. Furthermore, reserpine depletes noradrenaline from, and increases the synthesis and activity of the catecholamine-synthesizing enzyme tyrosine hydroxylase in, this nucleus. We have found by in situ hybridization of specific 35S-labelled oligonucleotide probes that a single dose of reserpine (10 mg/kg) induced a significant (70-145%) and long-lasting (up to at least 3 days) increase in the amount of galanin and neuropeptide Y mRNA in the locus coeruleus (along with the characteristic increase in tyrosine hydroxylase mRNA). These results suggest a similar reserpine-sensitive mechanism of galanin, neuropeptide Y and tyrosine hydroxylase gene regulation.