Histochemical demonstration of GABA-like immunoreactivity in cobalt labeled neuron individuals in the insect olfactory pathway

Individual olfactory neurons in the antennal lobes of Periplaneta americana were investigated for their morphological and neurochemical properties by means of intracellular cobalt injection and indirect peroxidase-antiperoxidase immunohistochemistry. GABA-like immunoreactivity was demonstrated in many local interneurons but not in uniglomerular projection neurons.