Taurine Transporters And Brain Taurine Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$226,034.00
Summary
Taurine is a very abundant amino acid in the brains of all mammals. Some animals such as cats gain almost all their taurine from their diet; others such as rats make significant amounts of taurine themselves; humans lie somewhere between these two extremes. Despite the variation in sources of taurine it has been standard practise for well over a decade to include taurine in human infant milk formulae because lack of dietary taurine in kittens leads to epileptic fits and abnormalities in brain de ....Taurine is a very abundant amino acid in the brains of all mammals. Some animals such as cats gain almost all their taurine from their diet; others such as rats make significant amounts of taurine themselves; humans lie somewhere between these two extremes. Despite the variation in sources of taurine it has been standard practise for well over a decade to include taurine in human infant milk formulae because lack of dietary taurine in kittens leads to epileptic fits and abnormalities in brain development, whilst in adult cats death of cells such as photoreceptors (in the eye) is also observed. Despite these observations we have very little knowledge as to what taurine does in the brain because we have no selective drugs to examine the site or sites of taurine action. We hypothesise that taurine might mediate its actions by modifying the intracellular and extracellular levels of other neurotransmiters, especially glutamate. We plan to examine the brains and retinas of adult cats and kittens which have been given a diet deficient in taurine. We will determine the levels of each of the main neurotransmitters in the brain, both as global assays of whole tissues and at the cellular level by immunocytochemistry. We will examine whether there are any compensatory changes in levels of expression of taurine transporters as the body becomes depleted of taurine (since taurine content of nerve cells will be regulated by uptake of taurine in the absence of endogenous synthesis). Expression of glutamate transporters will also be examined. By understanding the way that the major neurotransmiter systems respond to a reduction in taurine levels we hope to generate both descriptive and predictive models that define the roles of taurine in the mammalian nervous system and which may give insights into mechanisms of significant human disease processes including epilepsy and a series of conditions involving degeneration of photoreceptors.Read moreRead less