Glycine-insensitive NMDA-sensitive receptor expressed in Xenopus oocytes by guinea pig cerebellar mRNA.
The electrophysiological and pharmacological properties of N-methyl-D-aspartate (NMDA)-sensitive receptors expressed in Xenopus oocytes by injection of total poly(A)+RNAs (mRNAs) from the cerebellum and cerebrum of guinea pigs were compared. The inward current induced by NMDA under voltage-clamp in cerebellar mRNA-injected oocytes was depressed in a voltage-dependent fashion by Mg2+ to show a negative slope conductance and selectively antagonized by D-2-amino-5-phosphonovalerate (D-APV) and phencyclidine (PCP). Glycine (0.01-10 microM) did not potentiate NMDA-induced currents in cerebellar mRNA-injected oocytes, while it potentiated NMDA-induced currents in cerebral mRNA-injected oocytes in a dose-dependent fashion. 6-Cyano-7-nitroquinoxaline-2,3-dione and 7-chlorokynure-nate suppressed the NMDA response but significantly less potently in cerebellar mRNA-injected oocytes than in cerebral mRNA-injected oocytes. These results suggest that the NMDA-sensitive receptor expressed in Xenopus oocytes by guinea pig cerebellar mRNA resembles the cerebral NMDA receptor in its high sensitivities to Mg2+, PCP, and D-APV, but it is distinct from the cerebral NMDA receptor in responsiveness to glycine.
Sekiguchi
M
M
Department of Pharmacology, National Defense Medical College, Saitama, Japan.
Okamoto
K
K
Sakai
Y
Y
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D002531:Cerebellum / Q000378:metabolism*; D004553:Electric Conductivity; D005260:Female; D005998:Glycine / Q000494:pharmacology*; D006168:Guinea Pigs; D007736:Kynurenic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D016202:N-Methylaspartate; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010622:Phencyclidine / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics*; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000235:genetics*; D014982:Xenopus laevis
D011810:Quinoxalines; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D001224:Aspartic Acid; D016202:N-Methylaspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D015763:2-Amino-5-phosphonovalerate; D007736:Kynurenic Acid; D008274:Magnesium; D010622:Phencyclidine; C057013:7-chlorokynurenic acid; D005998:Glycine