Glutamate is the primary excitatory transmitter in the suprachiasmatic nucleus (SCN). Ionotropic glutamate receptors (iGluRs) mediate transduction of light information from the retina to the SCN, an important circadian clock phase shifting pathway. Metabotropic glutamate receptors (mGluRs) may play a significant modulatory role. mGluR modulation of SCN responses to glutamate was investigated wi...

Abnormalities in L-glutamic acid (glutamate) and GABA signal transmission have been postulated to play a role in depression, but little is known about the underlying molecular determinants and neural mechanisms. Microarray analysis of specific areas of cerebral cortex from individuals who had suffered from major depressive disorder demonstrated significant down-regulation of SLC1A2 and SLC1A3, ...

We measured the activities of two mitochondrial enzymes, the mitochondrial form of aspartate aminotransferase (EC 2.6.1.1) and glutamate dehydrogenase (EC 1.4.1.2), in the serum of apparently healthy persons (n = 84) and patients suffering from chronic liver diseases (n = 43). The distribution of activities for glutamate dehydrogenase, but not mitochondrial aspartate aminotransferase, was sex-d...

Previously, we demonstrated that the endogenous glutamate receptor antagonist kynurenic acid dose-dependently and significantly affected rat heart mitochondria. Now we have investigated the effects of L-tryptophan, L-kynurenine, 3-hydroxykynurenine and kynurenic, anthranilic, 3-hydroxyanthranilic, xanthurenic and quinolinic acids on respiratory parameters (ie, state 2, state 3), respiratory con...

Recent studies indicate that l-glutamate (l-Glu), abundant in many foods, is a stimulator of gastric vagal afferent nerves. The aim of the present study was to examine the possibility that l-Glu supplementation of a protein-rich liquid diet may prevent the incidence of diarrhoea during repetitive intra-gastric tube feeding. The gastric vagal afferent nerve recording of rats indicated that intra...

The effects of NPY(13-36) on cardiorespiratory responses elicited by microinjections of L-glutamate into the nucleus tractus solitarius (NTS) have been studied in anaesthetized (alpha-chloralose + urethane) Sprague-Dawley rats. NPY(13-36) in doses ranging from 50 to 500 fmol produces a significant increase in mean arterial pressure (MAP) without significant effects on heart rate (HR) and respir...

L-Glutamate transport by the H(+)-glutamate and Na(+)-glutamate symport proteins of Escherichia coli K-12 (GltPEc and GltSEc, respectively) and the Na(+)-H(+)-glutamate symport proteins of Bacillus stearothermophilus (GltTBs) and Bacillus caldotenax (GltTBc) was studied in membrane vesicles derived from cells in which the proteins were either homologously or heterologously expressed. Substrate ...

Cell-free extracts of Bacillus licheniformis and B. cereus were found to contain high specific activities of nicotinamide adenine dinucleotide phosphate (NADP)-dependent-l-glutamate dehydrogenase [EC 1.4.1.4; l-glutamate: NADP oxidoreductase (deaminating)]. Maximum specific activities were found in extracts of cells during the late exponential phase of growth when ammonium ion served as the sol...

The role of glutamate receptor within the nucleus accumbens in morphine tolerance has been postulated. Previous studies have reported that glutamate receptors exert their effects in part through the release of nitric oxide (NO). In the present study the effects of intra-accumbal injections of L-arginine (0.3, 1, and 3 ?g/rat), the NO precursor and L-NAME (0.3, 1, and 3 ?g/rat), the NOS inhibito...