Cerebrospinal fluid gamma aminobutyric acid levels in migraine.

Gamma-Aminobutyric acid (GABA) levels in cerebrospinal fluid were measured in seven patients with tension headache and 12 patients with migraine. GABA was detected only during the migraine attack. The results suggest disordered GABA metabolism in migraine.     

Inhibition of insulin hyperphagia by gamma aminobutyric acid antagonists in rats

The effects of GABA antagonists, picrotoxin and bicuculline were studied on hyperphagia caused by insulin in free feeding rats. It was found that peripheral administration of GABA antagonists inhibited this hyperphagia. These agents were administered in the VMH and LH through stereotaxically implanted cannulae. It was found that the food intake was inhibited when injected into the VMH, but not in the LH. These findings suggest that LH plays a relatively passive role as compared to VMH, where GABA appears to be an important neurotransmitter.     

尼氟灭酸对γ-氨基丁酸激活DRG神经元电流的作用

目的:观察尼氟灭酸(NFA)对大鼠背根神经节(DRG)神经元γ-氨基丁酸(GABA)激活电流的调制作用。方法:在新鲜分离的大鼠DRG神经元,应用全细胞膜片钳技术记录NFA和GABA激活电流。结果:部分DRG神经元(21/48,43.75%)外加NFA(0.1～100μmol/L)能引起浓度依赖性的外向电流,而大多数DRG神经元(150/159,94.32%)外加GABA(0.1～100μmol/L)则引起明显的浓度依赖性的内相电流。NFA-(100μmol/L)和GABA-(100μmol/L)激活电流的幅值分别是(0.27±0.06)nA(n=12)和(1.29±0.72)nA(n=53)。然而,预使用NFA(0.1～100μmol/L)能明显的抑制GABAA受体介导的内向电流。NFA的这一抑制作用也具有明显的浓度依赖性。但NFA没有改变GABA激活内向电流的EC50(大约30μmol/L)和翻转电位(大约-10mV)(P>0.05)。结论:预加NFA对GABA激活电流的峰值有明显的浓度依赖性的抑制作用。     

Correlation of myosin light chain phosphorylation and gamma aminobutyric acid receptors in Ascaris suum muscle

Four different muscle relaxants were compared as to their effects on tonic Ascaris suum muscle to: physiological activity, intracellular response to regulatory light chain phosphorylation, and receptor pharmacology. Perfusion of Ascaris suum muscle with each relaxant, gamma-aminobutyric acid, avermectin, piperazine and chlorpromazine resulted in a dose-dependent loss of muscle tone. Comparison of intracellular effects indicated that gamma-aminobutyric acid and avermectin perfusion initiated an increase in the levels of dephosphorylated regulatory light chain while piperazine increased first site phosphorylation and chlorpromazine increased second site phosphorylation. Receptor pharmacology studies were used to compare the actions of gamma-aminobutyric acid and piperazine. It was found that bicuculline-methiodide and picrotoxin inhibited the effects of gamma-aminobutyric acid in a dose-dependent manner, but these drugs had no effect on muscle relaxation stimulated with piperazine.     

谷氨酸棒杆菌S9114摇瓶发酵产γ-氨基丁酸的研究

为实现谷氨酸棒杆菌工业化生产γ-氨基丁酸(GABA),对L-谷氨酸工业生产菌S9114进行代谢途径改造。通过构建一株工程菌株S9114/p JYW-4-gad B1-gad B2,将来源于短乳杆菌Lb85菌株的谷氨酸脱羧酶编码基因gad B1和gad B2进行共表达,实现发酵72 h后发酵液中GABA含量达到32.8 g/L,GABA糖酸转化率达到47.3%。通过敲除该菌株的谷丙转氨酶编码基因ala T,使工程菌株S9114Δala T/p JYW-4-gad B1-gad B2发酵液中L-丙氨酸浓度降低5.5%,进一步降低了发酵副产物的含量。研究结果为利用谷氨酸棒杆菌实现工业化生产γ-氨基丁酸提供了有价值的参考。     

Localisation of gamma aminobutyric acid (GABA)-like immunoreactivity in the echinoderm Asterias rubens

Gamma amino butyric acid (GABA) is believed to be the principal inhibitory neurotransmitter in the mammalian central nervous system, a function that has been extended to a number of invertebrate systems. We have used a specific antiserum raised against GABA to demonstrate GABA-like immunoreactivity in the radial nerve cord (RNC), tube feet and the digestive system of the asteroid Asterias rubens. In the RNC, immunoreactivity was restricted to ectoneural fibres and cell bodies while in the tube feet fibres were revealed in the basal nerve ring and longitudinal nerve. In the gut, extensive labelling was apparent in the basi-epithelial plexus as well as in mucosal perikarya.     

Butyrylcholinesterase fluctuation in male albino rats with intracerebroventricular injection of gamma aminobutyric acid, muscimol, and picrotoxin

The effects of intracerebroventricular injection of gamma-Aminobutyric acid, muscimol, or picrotoxin have been studied on butyrylcholinesterase (BuChE) activities in the serum and several hypothalamic nuclei using biochemical, histochemical, and cytophotometric techniques, respectively. The blood samples were withdrawn from indwelling catheters in jugular vein 1, 15, 30, 45, 60, 90, and 120 min after injection of the drugs. Biochemical estimations demonstrated a significant inhibition of BuChE after GABA and muscimol injections, whereas a pronounced stimulation of BuChE was observed after injection of picrotoxin. The peak changes were observed within 30 min of drug injection. Cytophotometric studies have appeared to dovetail the biochemical findings. Only a marginal decrease was observed after injection of GABA in all nuclei, while muscimol induced a very conspicuous decrease of BuChE. On the contrary, intracerebroventricularly administered picrotoxin markedly increased the levels of BuChE activity. Thus it could be concluded that probably GABA and muscimol along with picrotoxin appear to alter BuChE.     

The metabolism of gamma aminobutyric acid in the lobster nervous system. Enzymes in single excitatory and inhibitory axons

γ-aminobutyric acid (GABA) is the inhibitory transmitter compound at the lobster neuromuscular junction. This paper presents a comparison of the enzymes of GABA metabolism in single identified inhibitory and excitatory axons from lobster walking legs. Inhibitory axons contain more than 100 times as much glutamic decarboxylase activity as do excitatory axons. GABA-glutamic transaminase is found in both excitatory and inhibitory axons, but about 50% more enzyme is present in inhibitory axons. The kinetic and electrophoretic behavior of the transaminase activity in excitatory and inhibitory axons is similar. Succinic semialdehyde dehydrogenase is found in both axon types, as is an unknown enzyme which converts a contaminant in radioactive glutamic acid to GABA. In lobster inhibitory neurons, therefore, the ability to accumulate GABA ultimately rests on the ability of the neuron to accumulate the enzyme glutamic decarboxylase.     

Pre-ischemic treadmill training affects glutamate and gamma aminobutyric acid levels in the striatal dialysate of a rat model of cerebral ischemia

AimsTreadmill training has been shown to improve function in animal models and patients with cerebral ischemia. However, the neurochemical effects of this intervention on the ischemic brain have not been well studied. This study was designed to evaluate the effects of pre-ischemic treadmill training on the release of glutamate and γ-aminobutyric acid (GABA) from the striatum in a rat middle cerebral artery occlusion (MCAO) model.Main methodsRats were divided into five groups: sham control without MCAO, and 0, 1, 2 and 4 weeks pre-ischemic treadmill training. After training, cerebral ischemia was induced by MCAO for 120 min, followed by reperfusion. Microdialysis was used to collect dialysates from the striatum immediately before ischemia, and at 40, 80 and 120 min after ischemia, as well as at 40, 80, 120, 160, 200 and 240 min after reperfusion.Key findingsPre-ischemic treadmill training decreased glutamate release and increased GABA release during the acute phase of cerebral ischemia/reperfusion. Treadmill training for at least 2 weeks produced statistically significant changes in GABA/glutamate release.SignificanceThe present study suggests that treadmill training inhibits the excessive release of glutamate, by stimulating GABA release during the acute phase of cerebral ischemia. This may be one of the important mechanisms to protect the striatal neurons from ischemic damage.     

Effect of ph, temperature and salinity on the production of gamma aminobutyric acid (GABA) from amines by marine bacteria

Abstract Bacteria isolated from sea-water grew on putrescine and spermidine as the sole carbon and nitrogen source, but not on cadaverine. Cell suspensions of one isolate (PU-8) produced gamma aminobutyric acid (GABA) from putrescine in 0.02 M phosphate buffer (pH 7.6) containing 0.33 M NaCl and 15 mM MgCl₂, and three other isolates produced the inducer when gabaculine (a natural inhibitor of GABA metabolism) was added. None of the isolates produced GABA from spermidine either in the absence or presence of gabaculine. Yields of GABA from putrescine were low in the suspension fluid and near stoichiometric quantities could only be obtained by extraction of incubations with methanol. Decreased NaCl (< 0.05 M) or increased pH resulted in an increase of GABA released into the suspension fluid during incubations, although in growth cultures only pH appeared to have a substantial effect. GABA release was not influenced by temperature in the range 17 to 32°C. Replacement of the normal concentration of NaCl (0.33 M) with equivalent LiCl, sodium glucuronate, or sucrose in cell suspensions did not result in increased GABA in the suspension fluid, indicating non-involvement of a sodium or chloride ion-dependent transport system in GABA release. The results show that marine bacteria can produce GABA, an inducer of marine invertebrate larval settlement, and indicate that extenal changes in osmotic pressure and pH which influence GABA release may be important factors to consider in the production of this inducer.