Cytochemical demonstration of aspartate aminotransferase activity in the rat retina.
The mitochondrial (m-AAT) and the cytoplasmic (c-AAT) isoenzyme activities of the glutamate synthesizing enzyme aspartate aminotransferase have been localized in the rat retina on the ultrastructural level using enzyme histochemistry. Reaction product of c-AAT was found selectively in cone pedicles, in presynaptic terminals of a subpopulation of amacrine cells and of horizontal cell processes, which are connected to rods. Rod spherules, terminals of cone-related horizontal cells and of bipolar cells reacted negatively, as well as ganglion cells, nerve fibre layer and optic nerve, m-AAT reaction product was found in all neuronal structures, most densely in the photoreceptor inner segments. The localization of c-AAT activity is in accordance with its presumed meaning in the production of releasable glutamate.
Gebhard
R
R
Department of Anatomy, University of Würzburg, Germany.
D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism*; D003593:Cytoplasm / Q000201:enzymology; D005260:Female; D006651:Histocytochemistry; D007527:Isoenzymes; D008297:Male; D008928:Mitochondria / Q000201:enzymology / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000201:enzymology* / Q000648:ultrastructure; D013569:Synapses / Q000201:enzymology
D007527:Isoenzymes; D001219:Aspartate Aminotransferases