[3H]muscimol labels neurons in both the superficial and deep layers of cat superior colliculus.
We examined the pattern of [3H]muscimol labeling in cat superior colliculus to determine if it matches that of [3H] gamma-aminobutyric acid ([3H]-GABA) labeling or GABA antibody immunoreactivity. Injections in the superficial layers labeled cell bodies in only the superficial layers. Of 204 labeled cells, 68% were located within the upper 200 microns of the superior colliculus, 31% within the deep superficial gray layer, and only 1% below that layer, a pattern similar to that seen with [3H]GABA labeling. By contrast, an injection in the deep layers of the colliculus resulted in cell labeling in both the superficial and deep layers, including 68% in the superficial gray layer, 24% in the optic layer, and 8% in the intermediate and deep gray layers. This pattern approximates that seen with GABA immunocytochemistry. We conclude that the pattern of accumulation of [3H]muscimol depends critically upon the location of the injection and reasonably matches the pattern of GABA immunoreactivity if the injection involves the deep layers of the colliculus.
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Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee, Memphis 38163.
White
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D000818:Animals; D001345:Autoradiography; D002415:Cats; D008854:Microscopy, Electron; D009118:Muscimol / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D013477:Superior Colliculi / Q000166:cytology / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D009118:Muscimol; D005680:gamma-Aminobutyric Acid