Taurine-Induced Potentiation is Partially Reversed by Low-Frequency Synaptic Stimlation
Neuroinhibitory actions of taurine in the brain are well known to be mediated by the activation of GABAA receptors11. We have recently reported a new neuromodulatory taurine action in the hippocampus independent of this GABA receptor type8,9. The new taurine action consists of a long-lasting potentiation of synaptic transmission, that is induced when taurine is applied at a concentration of 5–10 mM over a 10–30 min period. Excitatory postsynaptic potentials (EPSP) increase during taurine application, remaining elevated long after taurine withdrawal (at least three hours). This new taurine action could have important relevance to brain function, since persistent changes in the synaptic strength are envisaged as the cellular substrate of learning and memory4. Taurine-induced potentiation, unlike long-term potentiation (LTP) induced by high frequency synaptic stimulation of afferent fibers, is independent of NMDA receptor activation8. Nevertheless, taurine-induced potentiation has some points in common with LTP, primarily because its induction requires a rise in intracellular calcium, and both potentiation phenomena occlude mutually (Del Olmo et al., in preparation).
KeywordsMagnesium Depression Retina CaCl NMDA
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