Characterization of spontaneous excitatory synaptic currents in newt retinal bipolar cells

NEUROSCIENCE LETTERS

卷:271

Article

Kawai, F

关键词: AMPA;    glutamate;    desensitization;    off-bipolar cell;    retina;    newt;   

DOI  :  10.1016/S0304-3940(99)00511-X

来源: Elsevier

【 摘 要 】

The kinetics of glutamate concentration in the synaptic cleft is an important determinant of synaptic function. To elucidate peak concentration of glutamate released from a single vesicle in the cleft, spontaneous excitatory postsynaptic currents (sEPSCs) in Off-bipolar cells from the sliced newt retina were analyzed using whole-cell patch clamp recording and the computer simulation. The sEPSCs were blocked by an AMPA/kainate (KA) antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and prolonged by cyclothiazide. However, an N-methyl-D-aspartate (NMDA) antagonist, D-2-amino-5-phosphonopentanoic acid (D-AP5), was ineffective. These suggest that sEPSCs in Off-bipolar cells are mediated exclusively by AMPA/KA receptors. sEPSCs simulated by a detailed kinetic model of AMPA receptor best approximated the data, when peak glutamate concentration was 10 mu M. Therefore, it was concluded that peak concentration of glutamate released from a single vesicle would be elevated to approximately 10 mu M at the newt Off-bipolar dendrite. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

【 授权许可】

Free