Amino acid neurotransmitters and dopamine in brain and pituitary of the goldfish: involvement in the regulation of gonadotropin secretion

Abstract: An isocratic high-performance liquid chromatographic technique was developed to measure levels of yaminobutyric acid (GABA), glutamate, and taurine in the brain and pituitary of goldfish. Accuracy of this procedure for quantification of these compounds was established by evaluating anesthetic and postmortem effects and by selectively manipulating GABA concentrations by intraperitoneal administration of the glutamic acid decarboxylase (GAD) inhibitor 3-mercaptopropionic acid or the GABA transaminase inhibitor y-vinyl GABA. The technique provided a simple, rapid, and reliable method for evaluating the concentrations of these amino acids without the use of complex gradient chromatographic systems. To investigate the relationship between neurotransmitter amino acids and the control of pituitary secretion of gonadotropin, the effects of injection of taurine, GABA, or monosodium glutamate on GABA, glutamate, taurine, and, in some instances, monoamine concentrations in the brain and pituitary were evaluated and related to serum gonadotropin levels. Injection of taurine caused an elevation in serum gonadotropin concentrations. In addition, injection of the taurine precursor hypotaurine but not the taurine cataboiite isetheonic acid elevated serum gonadotropin levels. Intracerebroventricular injection of either GABA or taurine also elevated serum gonadotropin concentrations. Pretreatment of recrudescent fish with a-methyl-p-tyrosine reduced pituitary dopamine concentrations and also potentiated the serum gonadotropin response to taurine. Injection of monosodium glutamate caused an increase of glutamate content in the pituitary at 24 h; this was followed by a decrease at 72 h after administration. Pituitary GABA, taurine, and dopamine concentrations underwent a transient depletion after monosodium glutamate administration, and this was associated with an elevation of serum gonadotropin content. The increase in serum gonadotropin concentrations in response to a gonadotropin-releasing hormone analogue was potentiated by pretreatment with monosodium glutamate. This article demonstrates that procedures causing elevation in GABA and taurine concentrations stimulate gonadotropin release in a teleost fish. Key Words: y-Aminobutyric acidGlutamate-TaurineDopamine-Gonadotropin-Goldfish. Sloley B. D. et al. Amino acid neurotransmitters and dopamine in brain and pituitary of the goldfish: Involvement in the regulation of gonadotropin secretion. J. Neurochem. 58,2254Neurochem. 58, -2262

Towards a matrix mechanics framework for dynamic protein network

Protein–protein interaction networks are currently visualized by software generated interaction webs based upon static experimental data. Current state is limited to static, mostly non-compartmental network and non time resolved protein interactions. A satisfactory mathematical foundation for particle interactions within a viscous liquid state (situation within the cytoplasm) does not exist nor do current computer programs enable building dynamic interaction networks for time resolved interactions. Building mathematical foundation for intracellular protein interactions can be achieved in two increments (a) trigger and capture the dynamic molecular changes for a select subset of proteins using several model systems and high throughput time resolved proteomics and, (b) use this information to build the mathematical foundation and computational algorithm for a compartmentalized and dynamic protein interaction network. Such a foundation is expected to provide benefit in at least two spheres: (a) understanding physiology enabling explanation of phenomenon such as incomplete penetrance in genetic disorders and (b) enabling several fold increase in biopharmaceutical production using impure starting materials

Effects of American ginseng (Panax quinquefolius) on neurocognitive function: an acute, randomised, double-blind, placebo-controlled, crossover study

Over the last decade, Asian ginseng (Panax ginseng) has been shown to improve aspects of human cognitive function. American ginseng (Panax quinquefolius) has a distinct ginsenoside profile from P. ginseng, promising cognitive enhancing properties in preclinical studies and benefits processes linked to human cognition. The availability of a highly standardised extract of P. quinquefolius (Cereboost (TM)) led us to evaluate its neurocognitive properties in humans for the first time. This randomised, double-blind, placebo-controlled, crossover trial (N = 32, healthy young adults) assessed the acute mood, neurocognitive and glycaemic effects of three doses (100, 200 400 mg) of Cereboost (TM) (P. quinquefolius standardised to 10.65% ginsenosides). Participants' mood, cognitive function and blood glucose were measured 1, 3 and 6 h following administration. There was a significant improvement of working memory (WM) performance associated with P. quinquefolius. Corsi block performance was improved by all doses at all testing times. There were differential effects of all doses on other WM tasks which were maintained across the testing day. Choice reaction time accuracy and 'calmness' were significantly improved by 100 mg. There were no changes in blood glucose levels. This preliminary study has identified robust working memory enhancement following administration of American ginseng. These effects are distinct from those of Asian ginseng and suggest that psychopharmacological properties depend critically on ginsenoside profiles. These results have ramifications for the psychopharmacology of herbal extracts and merit further study using different dosing regimens and in populations where cognition is fragile

Identification of flavinoids as monoamine oxidase inhibitors and potential neuroprotectants in extracts of Ginkgo biloba leaves

In press: YesNRC publication: Ye