RT Journal Article
T1 Taurine potentiates presynaptic NMDA receptors in hippocampal Schaffer collateral axons
A1 Suárez González, Luz María
A1 Solís, Jose María
AB We have previously shown that activation of presynaptic N-methyl-d-aspartate (NMDA) receptors (NMDAR) enhances the amplitude of the presynaptic fibre volley (FV) evoked in Schaffer collateral axons of rat hippocampal slices, by a mechanism independent of extracellular Ca2+. Here we compared the pharmacological characteristics of presynaptic NMDARs affecting axon excitability (activated by 10–300 µm NMDA for 10 min), with those mediating field excitatory postsynaptic potentials (NMDA-fEPSP). We found that NMDA-induced potentiation was completely inhibited by NVP-AAM077, an antagonist of NR2A-containing NMDAR, but not by ifenprodil, an NR2B-selective antagonist. The inhibitor of the glycine-binding site in NMDARs, 7-clorokynurenic acid (7-CK), was more potent against NMDA-fEPSP (IC50 = 6.3 ± 1.3 µm) than against the NMDA-induced FV potentiation (IC50 = 26.5 ± 1.3 µm). Moreover, both post- and presynaptic NMDAR-mediated phenomena were enhanced by glycine and d-serine, but taurine, an endogenous analogue of glycine, only enhanced the latter (EC50 = 19 µm). Taurine was able to block the inhibitory effect of low doses of 7-CK on NMDA-induced FV potentiation, while glycine and d-serine only reduced the effects of higher concentrations of this drug. Surprisingly, the enhancing effect of taurine on NMDA-induced FV potentiation was blocked when it was co-applied with glycine. Furthermore, the glutamate released synaptically with a train of stimuli also increased FV amplitude by a mechanism dependent on NMDARs; this was potentiated by taurine but not by co-application of taurine and glycine. These results reveal that presynaptic NMDARs have unique properties that mediate the facilitation of axon excitability.
PB Wiley
SN 0953-816X
YR 2006
FD 2006
LK https://hdl.handle.net/20.500.14352/101062
UL https://hdl.handle.net/20.500.14352/101062
LA eng
NO Suárez, L.M. and Solís, J.M. (2006), Taurine potentiates presynaptic NMDA receptors in hippocampal Schaffer collateral axons. European Journal of Neuroscience, 24: 405-418. https://doi.org/10.1111/j.1460-9568.2006.04911.x
NO Ministerio de Sanidad y Consumo (España)
DS Docta Complutense
RD 7 abr 2025