title: Immunocytochemistry of GABA in the antennal lobes of the sphinx moth Manduca sexta.
abstract: We have prepared and characterized specific rabbit antisera against gamma-aminobutyric acid (GABA) coupled covalently to bovine serum albumin and keyhole-limpet hemocyanin. Using these antisera in immunocytochemical staining procedures, we have probed the antennal lobes and their afferent and efferent fiber tracts in the sphinx moth Manduca sexta for GABA-like immunoreactivity in order to map putatively GABAergic central neurons in the central antennal-sensory pathway. About 30% of the neuronal somata in the large lateral group of cell bodies in the antennal lobe are GABA-immunoreactive; cells in the medial and anterior groups of antennal-lobe cells did not exhibit GABA-like immunoreactivity. GABA-immunoreactive neurites had arborizations in all of the glomeruli in the antennal lobe. Double-labeling experiments involving tandem intracellular staining with Lucifer Yellow and immunocytochemical staining for GABA-like immunoreactivity demonstrated that at least some of the GABA-immunoreactive cells in the antennal lobe are amacrine local interneurons. Several fiber tracts that carry axons of antennal-lobe projection neurons exhibited GABA-immunoreactive fibers. Among the possibly GABA-containing projection neurons are several cells, with somata in the lateral group of the antennal lobe, that send their axons directly to the lateral protocerebrum.
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000032:analysis*; D005260:Female; D007124:Immunoenzyme Techniques; D007915:Lepidoptera / Q000032:analysis*; D008297:Male; D009036:Moths / Q000032:analysis*; D009474:Neurons / Q000032:analysis / Q000648:ultrastructure; D009833:Olfactory Pathways / Q000032:analysis*; D012679:Sense Organs / Q000032:analysis*; D012737:Sex Factors; D005680:gamma-Aminobutyric Acid / Q000032:analysis* / Q000276:immunology
chemical_list: D005680:gamma-Aminobutyric Acid