Amino acid concentrations and selected enzyme activities in rat auditory, olfactory, and visual systems.
Homogenates of specific brain regions of three sensory systems (auditory, olfactory, and visual) were prepared from pigmented Long-Evans Hooded rats and assayed for amino acid concentrations and activities of glutaminase, aspartate aminotransferase (total, cytosolic, and by difference, mitochondrial), malate dehydrogenase, lactate dehydrogenase, and choline acetyltransferase. Comparing the quantitative distributions among regions revealed significant correlations between AAT and aspartate, between glutaminase and glutamate, between glutamate and glutamine, and between AAT plus glutaminase, or glutaminase alone, and the sum of aspartate, glutamate, and GABA, suggesting a metabolic pathway involving the synthesis of a glutamate pool as precursor to aspartate and GABA. Of the inhibitory transmitter amino acids, GABA concentrations routinely exceeded those of glycine, but glycine concentrations were relatively high in brainstem auditory structures.
Ross
C D
CD
Department of Otorhinolaryngology, University of Oklahoma Health Sciences Center, Oklahoma City 73190, USA.
Godfrey
D A
DA
Parli
J A
JA
D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D001219:Aspartate Aminotransferases / Q000032:analysis; D001224:Aspartic Acid / Q000032:analysis; D001303:Auditory Cortex / Q000737:chemistry* / Q000201:enzymology; D002795:Choline O-Acetyltransferase / Q000032:analysis; D018698:Glutamic Acid / Q000032:analysis; D005972:Glutaminase / Q000032:analysis; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008291:Malate Dehydrogenase / Q000032:analysis; D009833:Olfactory Pathways / Q000737:chemistry* / Q000201:enzymology; D051381:Rats; D014018:Tissue Distribution; D014793:Visual Cortex / Q000737:chemistry* / Q000201:enzymology
D000596:Amino Acids; D001224:Aspartic Acid; D018698:Glutamic Acid; D007770:L-Lactate Dehydrogenase; D008291:Malate Dehydrogenase; D002795:Choline O-Acetyltransferase; D001219:Aspartate Aminotransferases; D005972:Glutaminase