TY - JOUR
T1 - A method for evaluating chemical selectivity of agonists for glutamate receptor channels incorporated in liposomes based on an agonist-induced ion flux measured by ion-selective electrodes
AU - Radecka, Hanna
AU - Nakanishi, Jun
AU - Hirano, Ayumi
AU - Sugawara, Masao
AU - Umezawa, Yoshio
N1 - Funding Information:
The authors thank J. Yamamichi for his experimental help in protein isolation and Dr K. Tohda for preparing ion-selective electrodes. One of the authors (H.R.) acknowledges Japan Society for the Promotion of Science for the Invitation Fellowship Programs for Research in Japan (long term) for foreign researchers. This work was supported from Grants for Scientific Research by the Ministry of Education, Science and Culture, Japan. The supports from Suntory Institute for Bioorganic Research are also acknowledged.
PY - 1999/2
Y1 - 1999/2
N2 - A new method for evaluating chemical selectivity of agonists for the NMDA subtype of glutamate receptor (GluR) channels is described. The method is based on the magnitude of Ca2+ release from GluR-incorporated liposomes, which is measured by a Ca2+ ion-selective electrode with a thin-layer mode. The partially purified GluRs from rat whole brain were reconstituted into Ca2+-loaded liposomes. Small aliquots (each 50 μl) of the proteoliposomes, in the presence of an antagonist DNQX for blocking non-NMDA subtype, were subjected to potentiometric measurements of Ca2+ release under stimulation by three kinds of agonists, i.e. NMDA, l-glutamate and l-CCG-IV. The amount of the Ca2+ ion flux through the GluR channel induced by the agonists was found to increase in the order of NMDA2+ flux through the NMDA receptor, i.e. the extent of signal transduction by a given agonist. The evaluation of agonist selectivity based on Na+ release was also investigated by using a Na+ ion-selective electrode, but agonist-induced Na+ release was not detected, because of low permeability of Na+ through the NMDA subtype. Copyright (C) 1999 Elsevier Science B.V.
AB - A new method for evaluating chemical selectivity of agonists for the NMDA subtype of glutamate receptor (GluR) channels is described. The method is based on the magnitude of Ca2+ release from GluR-incorporated liposomes, which is measured by a Ca2+ ion-selective electrode with a thin-layer mode. The partially purified GluRs from rat whole brain were reconstituted into Ca2+-loaded liposomes. Small aliquots (each 50 μl) of the proteoliposomes, in the presence of an antagonist DNQX for blocking non-NMDA subtype, were subjected to potentiometric measurements of Ca2+ release under stimulation by three kinds of agonists, i.e. NMDA, l-glutamate and l-CCG-IV. The amount of the Ca2+ ion flux through the GluR channel induced by the agonists was found to increase in the order of NMDA2+ flux through the NMDA receptor, i.e. the extent of signal transduction by a given agonist. The evaluation of agonist selectivity based on Na+ release was also investigated by using a Na+ ion-selective electrode, but agonist-induced Na+ release was not detected, because of low permeability of Na+ through the NMDA subtype. Copyright (C) 1999 Elsevier Science B.V.
KW - Ca ion flux
KW - Ion-selective electrode
KW - Liposome
KW - NMDA receptor
KW - Selectivity of agonist
KW - Thin-layer potentiometry
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U2 - 10.1016/S0731-7085(98)00146-0
DO - 10.1016/S0731-7085(98)00146-0
M3 - Article
C2 - 10698582
AN - SCOPUS:0032898348
VL - 19
SP - 205
EP - 216
JO - Journal of Pharmaceutical and Biomedical Analysis
JF - Journal of Pharmaceutical and Biomedical Analysis
SN - 0731-7085
IS - 1-2
ER -