EFFECT OF DIABETES ON LEVELS AND UPTAKE OF PUTATIVE AMINO-ACID NEUROTRANSMITTERS IN RAT RETINA AND RETINAL-PIGMENT EPITHELIUM

Free amino acid levels and high affinity uptake of glutamate, aspartat e, gamma-aminobutyrate, glycine and taurine were studied in retina and retinal pigment epithelium of streptozotocin diabetic rats. Results s how that experimental diabetes produces a generalized fall in the cont ent of free amino acids in both retina and retinal pigment epithelium. With regard to the high affinity uptake, in the two tissues of diabet ic animals showed decreased aspartate uptake, enhanced taurine and gam ma-aminobutyrate uptake, whereas that of glycine and glutamate was unc hanged. These results might suggest that diabetes causes alterations o f specific amino acid transport systems and/or alterations of some cel l populations.