Function of GABA rho1 receptors is up-regulated by chronic GABA treatment in Xenopus oocytes.
This study was aimed to investigate the effect of chronic gamma-aminobutyric acid (GABA) treatment on homomeric GABA rho1 receptors expressed in Xenopus oocytes. The rho1 mRNA-injected oocytes were incubated with 10 mM GABA for 2, 6, 24, 48 or 72 h, prior to the assessment of GABA-gated ion currents. The results showed that GABA exposure for more than 6 h dramatically enhanced the peak GABA-activated currents. In addition to current amplitude, the apparent GABA potency and cooperativity were significantly increased. The enhancement reached its plateau after a 24-h exposure. The up-regulation of GABA current amplitude was completely inhibited by cycloheximide, a translation inhibitor. This suggests that chronic GABA treatment may increase the translational activity of GABA rho1 subunit in Xenopus oocytes.
Department of Pharmacology, Chang Gung University School of Medicine, Kweisan, Taoyuan, Taiwan. lhlin@mcw.edu
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D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D004553:Electric Conductivity; D005260:Female; D007536:Isomerism; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D018079:Receptors, GABA / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology*; D014981:Xenopus; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D011500:Protein Synthesis Inhibitors; D018079:Receptors, GABA; D005680:gamma-Aminobutyric Acid; D003513:Cycloheximide