Decrease in tyrosine hydroxylase, but not aromatic L-amino acid decarboxylase, messenger RNA in rat olfactory bulb following neonatal, unilateral odor deprivation.

Unilateral naris cauterization in rats results in occlusion of the affected naris and blockade of odorant access to ipsilateral olfactory receptor cells in the olfactory epithelium. These receptor cells project exclusively to the olfactory bulb (OB) and appear to regulate expression of the dopaminergic phenotype in a population of OB juxtaglomerular neurons. Unilateral odor deprivation results in a loss of normal stimulatory input to the OB and a marked and specific decrease in ipsilateral OB tyrosine hydroxylase (TH) expression.