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Modulation of extracellular calcium on miniature inhibitory postsynaptic currents of Xenopus' optic tectal neurons

Wang Hong, Cai Haoran

First Hospital，Central Laboratory, Peking University. Beijing 100034,China

Abstract

Experiments were performed to study the relationship between presynaptic calcium and minia-ture inhibitory postsynaptic currents (mIPSCs) using voltage-clamp technique with whole cell mode in Xe-nopus, optic tectal slices. The results are as follows: The frequency of mIPSCs decreased from 1. 91±0. 59Hz to 0. 34±0. 09 Hz in calcium-free solution (paired t test, P =0. 019, n = 8), the value of mIPSCs fre-quency being (25. 5±4. 4) % of control. In order to rule out the effect of remaining calcium in perfusingsolution we further applied calcium-free solution containing egtazic acid, ethyleneglycol-bis (β-aminoethyle-ther) -N, N'-tetraacetic acid (EGTA) (200 nmol/L - 2 mmol/L). The mIPSCs frequency changed from1. 57±0. 57 in control to 0. 89±0. 41 Hz in calcium-free solution containing EGTA (paired t test, P =0. 002, n = 12), decreasing to (40. 0±5. 9) % of control. There is no statistical difference in the resultsbetween Ca~(2+) -free perfusion and Ca~(2+) -free solution containing EGTA (paired t test, P = 0. 74,n=9).

Key words: Brain slice;Patch-clamp;Miniature inhibitory postsynaptic currents (mIPSCs); Calcium ryanodine receptor (RyR);;

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Citing This Article：

Wang Hong, Cai Haoran. Modulation of extracellular calcium on miniature inhibitory postsynaptic currents of Xenopus' optic tectal neurons. Acta Physiol Sin 2003; 55 (5): (in Chinese with English abstract).