Immunocytochemical localization of putative gamma-aminobutyric acid receptor subunits in the head ganglia of Periplaneta americana using an anti-RDL C-terminal antibody

A polyclonal antibody raised against a 17 amino acid polypeptide (the predi cted C-terminal sequence of the cloned Drosophila melanogaster gamma-aminob utyric acid (GABA) receptor subunit, RDL) was used to investigate the distr ibution of GABA receptor subunit(s) of this type in the nervous system of t he cockroach Periplaneta americana. Intense staining was detected in the ca lyces of the mushroom bodies, glomeruli of the antennal lobes, lower centra l body, the corpora cardiaca and several cell layers of the medulla and the lobula regions of the optic robe. The most intense Immunocytochemical stai ning was in the suboesophageal ganglion. Control sections pre-incubated wit h the primary antibody and conjugated peptide were not stained. Thus, it ap pears that a GABA receptor subunit of the RDL type is located in cockroach brain regions involved in the processing of visual, olfactory and mechanose nsory inputs to the nervous system. Since the corpora cardiaca reacted to t his antiserum, this type of GABA receptor may also be involved in the regul ation of neurosecretory activity. (C) 2000 Elsevier Science Ireland Ltd. Al l rights reserved.