Eosine-induced blockade of N-methyl-D-aspartate channels in acutely isolated rat hippocampal neurons.
Acutely isolated rat hippocampal neurons were voltage-clamped in the whole-cell configuration. The currents through N-methyl-D-aspartate (NMDA) channels were elicited by fast application of aspartate in a Mg(2+)-free 3 microM glycine-containing solution. Eosine, known as a potent reversible inhibitor of the plasma membrane Ca(2+) pump, proved to be able to induce a blockade of NMDA channels. The eosine-induced inhibition of NMDA-mediated currents enhanced with eosine concentration (IC(50) = 248 microM) but did not depend on the membrane potential, agonist (aspartate) or coagonist (glycine) concentrations, pH, or the presence of spermine, ethanol, and the disulfide-reducing agents dithiothreitol and glutathione. Zn(2+) inhibited NMDA channels with equal efficiency both in the presence and absence of eosine. These results suggest that eosine interacts with a new, previously unknown NMDA receptor regulatory site.
Sobolevsky
A I
AI
Institute of General Pathology and Pathophysiology, Moscow, Russia. rans@rans.msk.ru
Yelshansky
M V
MV
Khodorov
B I
BI
D000818:Animals; D004801:Eosine Yellowish-(YS) / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
D016194:Receptors, N-Methyl-D-Aspartate; D004801:Eosine Yellowish-(YS)