Immunocytochemical localization of GABA neurons and dopamine neurons in the rat main and accessory olfactory bulbs.

Immunocytochemical localization of GABA neurons and dopamine neurons in the rat olfactory bulb was obtained with sheep antiserum to glutamate decarboxylase (GAD) and rabbit antiserum to tyrosine hydroxylase (TH). GAD-positive neurons include periglomerular cells, granule cells, superficial and deep short axon cells. TH-positive neurons represent periglomerular cells. Two-color immunocytochemistry shows that GABA and dopamine periglomerular cells are separate populations. The accessory olfactory bulb has rare dopamine cells and few superficial short axon cells. Radial gradients of GAD-immunostaining are evident in the main but not in the accessory olfactory bulb.