TY - JOUR
T1 - Mode of blockade by MK-801 of N-methyl-d-aspartate-induced increase in intracellular Ca2+ in cultured mouse hippocampal neurons
AU - Yuzaki, Michisuke
AU - Miyawaki, Atsushi
AU - Akita, Kyoko
AU - Kudo, Yoshihisa
AU - Ogura, Akihiko
AU - Ino, Hidetoshi
AU - Mikoshiba, Katsuhiko
PY - 1990/5/28
Y1 - 1990/5/28
N2 - Microfluorometry with fura-2 was applied to study the action of the anticonvulsant (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) on N-methyl-d-aspartate (NMDA)-induced increase in intracellular Ca2+ concentration ([Ca2+]1) in cultured mouse hippocampal neurons. MK-801 caused a potent and long-lasting blockade of the NMDA-activated [Ca2+]i elevation in a selective manner, not affecting the [Ca2+]i rise induced by quisqualate or kainate. Blockade and recovery from the blockade by MK-801 showed use dependency; the degree of blockade was dependent on the presence of NMDA. The use-dependent onset of antagonism was, however, highly sensitive to the bath temperature. MK-801 applied in the absence of NMDA had no effect on the response to subsequent application of NMDA at 22°C, whereas it reduced the subsequent response to NMDA significantly at 37°C. MK-801 interacted with the receptor-ion channel complex even when Mg2+, which is considered to block the open channel, had already blocked the NMDA-induced [Ca2+]i. The recovery from blockade by MK-801 was not accelerated by the application of 10 mM Mg2+ for 5 min. These results suggest that MK-801 can gain access to its binding site in the absence of NMDA at physiological temperature, and that this binding site is distinct from that for Mg2+.
AB - Microfluorometry with fura-2 was applied to study the action of the anticonvulsant (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) on N-methyl-d-aspartate (NMDA)-induced increase in intracellular Ca2+ concentration ([Ca2+]1) in cultured mouse hippocampal neurons. MK-801 caused a potent and long-lasting blockade of the NMDA-activated [Ca2+]i elevation in a selective manner, not affecting the [Ca2+]i rise induced by quisqualate or kainate. Blockade and recovery from the blockade by MK-801 showed use dependency; the degree of blockade was dependent on the presence of NMDA. The use-dependent onset of antagonism was, however, highly sensitive to the bath temperature. MK-801 applied in the absence of NMDA had no effect on the response to subsequent application of NMDA at 22°C, whereas it reduced the subsequent response to NMDA significantly at 37°C. MK-801 interacted with the receptor-ion channel complex even when Mg2+, which is considered to block the open channel, had already blocked the NMDA-induced [Ca2+]i. The recovery from blockade by MK-801 was not accelerated by the application of 10 mM Mg2+ for 5 min. These results suggest that MK-801 can gain access to its binding site in the absence of NMDA at physiological temperature, and that this binding site is distinct from that for Mg2+.
KW - Calcium
KW - Cell culture
KW - Excitatory amino acid receptor
KW - Fura-2
KW - Hippocampus
KW - MK-801
KW - Magnesium
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U2 - 10.1016/0006-8993(90)91006-3
DO - 10.1016/0006-8993(90)91006-3
M3 - Article
C2 - 2165437
AN - SCOPUS:0025283379
VL - 517
SP - 51
EP - 56
JO - Molecular Brain Research
JF - Molecular Brain Research
SN - 0006-8993
IS - 1-2
ER -