The use of gabaculine-induced accumulation of GABA for an index of synthesis of GABA in the retina.
The characteristics of accumulation of gamma-aminobutyric acid (GABA) in the retina after an intravitreal injection of the GABA-T inhibitor, gabaculine, have been studied in rats. The accumulation of GABA after injection of gabaculine was both dosage- and time-dependent. In both dark- and light-adapted-retinas. GABA continued to increase linearly for at least 90 min after an injection of gabaculine and this increase (3-fold) was similar in dark- and light-adapted rats. The GABA agonist, muscimol, and the GABA antagonist, bicuculline methiodide, significantly inhibited and facilitated, respectively, the gabaculine-induced increase in GABA levels. Previous studies have shown that accumulation of GABA following the irreversible inhibition of GABA-T was useful for measuring the rate of synthesis of GABA in the central nervous system, and these studies suggest that this technique may also be useful in the retina.
D000221:Adaptation, Ocular / Q000187:drug effects; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology*; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis / Q000378:metabolism*
D003509:Cyclohexanecarboxylic Acids; D009118:Muscimol; C012987:gabaculine; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline