THE EFFECTS OF MUSCARINE AND ATROPINE REVEAL THAT INHIBITORY AUTORECEPTORS ARE PRESENT ON FROG MOTOR-NERVE TERMINALS BUT ARE NOT ACTIVATED DURING TRANSMISSION

被引:11
作者
ARENSON, MS [1 ]
机构
[1] UNIV LONDON ST BARTHOLOMEWS HOSP,COLL MED,DEPT PHARMACOL,LONDON EC1M 6BQ,ENGLAND
关键词
ACETYLCHOLINE RELEASE; MUSCARINIC AUTOINHIBITION; END-PLATE POTENTIAL; NEUROMUSCULAR TRANSMISSION; FROG;
D O I
10.1007/BF00168599
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
The role of presynaptic muscarinic receptors in modulating neuromuscular transmission was studied in the isolated sartorius muscle of the frog using electrophysiological techniques. In low calcium solutions muscarine reduced mEPP frequency and the quantal of EPPs. In solutions containing the normal calcium concentration the effect of muscarine on quantal content, but not the effect on mEPP frequency, was somewhat attenuated. Muscarine-induced reductions in the parameters of ACh release were prevented by atropine. Irrespective of the calcium concentration, atropine had no effect on mEPP frequency except where fibres were pretreated with glycerol. In experiments where evoked acetylcholine release was maintained at physiologically relevant levels, atropine had no effect on the quantal content of EPPs evoked at low frequency or on the extent of rundown in trains of EPPs evoked at high frequency.
引用
收藏
页码:128 / 133
页数:6
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