Physiological actions of taurine

Taurine in the central nervous system and the mammalian actions of taurine

Restraint stress in biomedical research: A review

Transmitter circuits in the vertebrate retina.

Chapter 1 GABAergic mechanisms in the retina

The effect of a stressful manipulation on the metabolism of gamma-aminobutyric acid (GABA) in the rat brain was studied. Application of an immobilized stress to animals induced a significant increase in the striatal and hypothalamic GABA contents without affecting those in other central structures examined. It was also found that the increase in striatal GABA level preceded that in the hypothalamus. This increase in steady-state levels of GABA in the striatum and hypothalamus disappeared at 12 h after the termination of the application of stress for 3 h, which exhibited a maximal stimulatory action on the GABA contents in both central areas. The activity of L-glutamic acid decarboxylase was found to be significantly elevated in the striatum and hypothalamus following the stress application with a concomitant decrease in the content of L-glutamic acid, which is converted to GABA by the catalytic action of the latter enzyme. The in vivo turnover of GABA in the brain was estimated by taking advantages of the postmortem accumulation of GABA following decapitation and of the selective inhibitory action of a low dose of aminooxyacetic acid on the GABA degrading system, respectively. Analysis using these two different methods revealed that the cerebral turnover of GABA in vivo was not significantly altered under stressful situations despite of the increase in its steady-state level. These results suggest that central GABA system may respond to the input of painful stimuli resulting from the application of a severe physical and psychological stressor, in addition to the well-known functional alterations in catecholamine neurons. The functional significance of these alterations in the central GABA neurons is also discussed.

Stress-induced alterations in metabolism of gamma-aminobutyric acid in rat brain.

Simultaneous determination of cysteine sulfinic acid and cysteic acid in rat brain by high-performance liquid chromatography.

Cerebral taurine biosynthesis in a spontaneously hypertensive rat (SHR) has been studied. Cysteine sulfinic acid (CSA) and cysteic acid (CA), possible key intermediates in taurine biosynthesis, were found in the rat brain, whereas no cysteamine-cystamine was detected. In the brain of SHR, a statistically significant decrease in the contents of CSA, CA, and taurine was noted in the cerebellum, hypothalamus, and striatum as compared with normotensive Wistar Kyoto rats. Similarly, it was demonstrated that the activity of cysteine dioxygenase, the enzyme catalyzing cysteine to CSA, was attenuated significantly in the same brain areas of SHR. In contrast, no alteration in the activity of CSA decarboxylase, the enzyme converting CSA to hypotaurine or CA to taurine, was observed. A decline in the percent conversion of [14C]cysteine to [14C]taurine was found also in tissue homogenates from the cerebellum, hypothalamus, and striatum of SHR, indicating that the declines in taurine content may be due to an attenuation of taurine biosynthesis, possibly at the step involving cysteine dioxygenase.

Alteration of cerebral taurine biosynthesis in spontaneously hypertensive rats

Determination of cystamine by high-performance liquid chromatography☆

The alteration of amino acids in cerebrospinal fluids (CSF) from 14 cases of Parkinson's disease, five cases of cerebellar degeneration and five cases of headache (control) was studied using high performance liquid chromatography. In patients with Parkinson's disease, it was found that the CSF level of GABA showed a significant decrease, while that of taurine had an increase. The degree of disability in Parkinson's disease and the decreased GABA levels had a positive correlation, especially at its advanced stages. In patients with cerebellar degeneration, it was also found that there was a significant decrease in CSF GABA. The present results suggest that the CSF level of GABA may be a good indicator of the severity of Parkinson's disease as well as the presence of cerebellar degeneration. Possible involvement of the increase of CSF taurine in the pathogenesis of Parkinson's disease is also suggested.

Shuji Ida

Papers

Stress-induced alterations in metabolism of gamma-aminobutyric acid in rat brain.

Simultaneous determination of cysteine sulfinic acid and cysteic acid in rat brain by high-performance liquid chromatography.

Alteration of cerebral taurine biosynthesis in spontaneously hypertensive rats

Determination of cystamine by high-performance liquid chromatography☆

Alteration of amino acids in cerebrospinal fluid from patients with Parkinson's disease and spinocerebellar degeneration.