title: Colocalization of gamma-aminobutyric acid and acetylcholinesterase in rodent cortical neurons.
abstract: We have previously demonstrated that neurons of the rat cerebral cortex which stain positively for acetylcholinesterase are not likely to be cholinergic since they do not colocalize with choline acetyltransferase immunoreactivity [Levey, Rye, Wainer, Mufson and Mesulam (1984) Neuroscience 9, 9-22]. These noncholinergic acetylcholinesterase-positive cells were similar in morphology to cortical neurons which localize gamma-aminobutyric acid or glutamate decarboxylase immunoreactivity. In order to investigate the possibility that the two substances may be colocalized to the same cortical neurons, gamma-aminobutyric acid immunohistochemistry and acetylcholinesterase histochemistry were combined in single sections of rat cerebral cortex. We found that 18% of gamma-aminobutyric acid-immunoreactive cortical neurons are also acetylcholinesterase-positive, and about 36% of acetylcholinesterase-positive cells are gamma-aminobutyric acid-immunoreactive. Neurons which colocalized both substances were multipolar and bipolar neurons in cortical laminae II-VI and were observed in every cortical area examined. The possibility that gamma-aminobutyric acid-immunoreactive/acetylcholinesterase-positive cortical neurons may be postsynaptic targets of cholinergic afferents to the cerebral cortex is discussed.
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis*; D000818:Animals; D002540:Cerebral Cortex / Q000032:analysis* / Q000166:cytology / Q000201:enzymology; D006651:Histocytochemistry; D007158:Immunologic Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
chemical_list: D005680:gamma-Aminobutyric Acid; D000110:Acetylcholinesterase