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Single channel properties of NMDA receptors in cortical neurons

Gao Tianming, Zou Fei, Chen Peixi

Department of Physiology, Sun Yat--Sen University of Medical Sciences. Guangzhou 510089, Guangdong

Abstract

The cell--attached and inside--out configurations of the patch-clamp techniques were used to investigate single channel properties of NMDA receptors in cultured intat neurons mechanically isolated from rat cereberal cortex. Recordings were made in Mg~(2+)--free solutions. A channel, with a conductance of 35 pS was studied in detail with either NMDA or L--aspartate in the patch pipette. NMDA channels were permeableto Na~(2+)and K~(+), but not to Cl~(-), the mean open times and open probabilities of these channels were decreased with increasing hyperpolarization. distributions for the open times, closed times and burst durations repuired two--component fits. Channel openings were supressed by APV. When Mg~(2+)was inclued in the pipette, the mean open tmes were significantly diminished in a concentration- and voltage--dependent manner. Decreasing the bath temperature prolonged channel open times and decreased current amplitudes. The results indicate that there is an intrinsic voltage dependence of NMDA channel kinetics in the intact neurons, suggesting that the normal function of the NMDA channel may be dependent on some intracellular biochemical process

Key words: Patch clamp;NMDA receptor channels;Conical neurons

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Citing This Article：

Gao Tianming, Zou Fei, Chen Peixi. Single channel properties of NMDA receptors in cortical neurons. Acta Physiol Sin 1995; 47 (2): (in Chinese with English abstract).