Jayakumar A R, Sujatha R, Paul V, Asokan C, Govindasamy S, Jayakumar R
Bio-organic and Neurochemistry Laboratory, Central Leather Research Institute, Adyar, Chennai - 600 020, India.
Brain Res. 1999 Aug 7;837(1-2):229-35. doi: 10.1016/s0006-8993(99)01692-3.
The results of the present study clearly shows that a correlation exists between nitric oxide (NO) and gamma-aminobutyric acid transaminase (GABAT-T) activity as well as gamma-aminobutyric acid (GABA), glutamic acid and the activity of glutamic acid decarboxylase (GAD). Supporting of this 10 min after the administration of L-Arginine (L-Arg) increased GABA concentration and diminished the activity of GABA-T. There was no change in GAD activity and glutamic acid level. Administration of convulsion inducing agent Picrotoxin (PCT) decreased the NO concentration in the brain and enhanced the activity of GABA-T, and the fact that the NOS inhibitor (N(G)-nitro-L-Arg methyl ester (L-NAME) diminished the activity of NOS and increased the activity of GABA-T provide another support for the involvement of NO on GABA-T activity. The present study clearly showed that high concentrations of NO in the brain suppresses the activity of GABA-T.
本研究结果清楚地表明，一氧化氮（NO）与γ-氨基丁酸转氨酶（GABAT-T）活性以及γ-氨基丁酸（GABA）、谷氨酸和谷氨酸脱羧酶（GAD）活性之间存在相关性。给予L-精氨酸（L-Arg）10分钟后，GABA浓度升高，GABA-T活性降低，支持了这一点。GAD活性和谷氨酸水平没有变化。给予惊厥诱导剂印防己毒素（PCT）可降低脑中NO浓度并增强GABA-T活性，而NOS抑制剂（N（G）-硝基-L-精氨酸甲酯（L-NAME）降低NOS活性并增加GABA-T活性这一事实为NO参与GABA-T活性提供了另一支持。本研究清楚地表明，脑中高浓度的NO会抑制GABA-T的活性。
