Histochemical support for a dopaminergic mechanism in the dendrites of certain periglomerular cells in the rat olfactory bulb.

With the Vibratome modification of the Falck-Hillarp technique, and with the indirect immunofluorescence technique for visualizing the first three enzymes in catecholamine synthesis, evidence has been obtained that in the rat olfactory bulb several periglomerular cells are dopaminergic. Both tyrosine hydroxylase and dopadecarboxylase, converting tyrosine to DOPA and DOPA to dopamine (DA), respectively, but not dopamine-beta-hydroxylase, converting DA to noradrenaline, are present in periglomerular cell bodies, as well as in their intraglomerular dendrites. These findings suggest that DA may be active at dendrodentritic synapses known to be present between periglomerular and mitral and/or tufted cells.