The effects of olfactory bulbectomy (OBX) on galanin (GAL) gene expres
sion in the locus coeruleus (LC) were examined with quantitative in si
tu hybridization histochemistry. OBX increased prepro-GAL levels 3 and
14 days after surgery, as compared to sham-operated controls. Levels
of mRNA encoding prepro-neuropeptide Y (NPY) were unchanged, and level
s of mRNA encoding tyrosine hydroxylase (TH) were elevated in the LC o
nly on day 3. The results indicate that GAL gene expression in the LC
increases after lesioning a terminal field.