Synaptic connections of dopamine-immunoreactive neurons in the antennal lobes of Periplaneta americana. Colocalization with GABA-like immunoreactivity.

Dopamine-like immunoreactivity was demonstrated histochemically in about ten local interneurons in the antennal lobe of Periplaneta americana. The somata of these neurons are within the ventrolateral group of cell bodies. Additional immunohistochemical tests revealed that the same neurons also have a GABA-like immunoreactivity. Immunohistochemical dopamine staining (preembedding) of preparations in which the antennal receptor fibers had been caused to degenerate showed that in the glomerular neuropil these antennal fibers form output synapses on dopamine-immunoreactive neurons. The latter form output synapses on unstained neuron profiles.