摘要
以蔗糖间隙法观察镧（Ｌａ３＋）对离体兔颈上交感神经节突触传递的影响。由顺向刺激诱发的复合神经节动作电位（ＡＰｃ），Ｎ电位（相当于快兴奋性突触后电位），以及后超极化和Ｐ电位（相当于慢抑制性突触后电位），被用作突触反应的指标。在浓度为２０，４０，８０和１６０μｍｏｌ·Ｌ－１时，ＬａＣｌ３减小ＡＰｃ和Ｎ波的幅度，而以ＬａＣｌ３灌流后，对节前神经干的动作电位并无明显影响。后超极化及Ｐ电位先有增大，继而也被抑制。ＬａＣｌ３（４０μｍｏｌ·Ｌ－１）可减弱无钙Ｋｒｅｂｓ液对ＡＰｃ的抑制效应。高钙（１０ｍｍｏｌ·Ｌ－１）则可拮抗ＬａＣｌ３对ＡＰｃ的抑制作用。４－氨基吡啶（０．１ｍｍｏｌ·Ｌ－１）可逆转ＬａＣｌ３对ＡＰｃ的抑制效应。外源性乙酰胆碱引起的神经节去极化，被ＬａＣｌ３所抑制。结果提示，Ｌａ３＋可通过突触前及突触后机制抑制颈上交感神经节的突触传递。
The effects of lanthanum (La3+) onthe synaptic transmission in isolated superior cervicalganglia of rabbits were investigated by means of thesucrose-gap method. The compound ganglionic actionpotential (APc), the N potential (corresponding to thefast excitatory postsynaptic potential). the after-hyperpolarization (AH) and the P potential (corre-sponding to the slow inhibitory postsynaptic potential)elicited from orthodromic stimulation were used as theindices of synaptic responses. At the concentrations of20, 40, 80 and 160 μmol·L-1, LaCl3 decreased theamplitude of APc and N potential, while that of the ac-tion potential recorded from the preganglionic nervetrunk showed no notable changes after superfusion withLaCl3. The AH and the P potential were first enhancedand, subsequently depressed. LaCl3 (40 μmol·L-1) ad-ding to the Ca2+-free Krebs solution attenuated thedepressant effect of Ca2+-free medium on APc, whereashigh Ca2+ (10 mmol·L-1) antagonized the inhibitoryeffect of LaCl3 on the APc. 4-Aminopyridine (0.1mmol·L-1) reversed the depressant effect of LaCl3 onthe APc. Depolarization induced by application ofexogenous acetylcholine was depressed by LaCl3. Theresults indicate that La3+ depresses the synaptic trans-mission of superior cervical ganglia by both pre-andpost-ganglionic mechanisms.
出处
《中国药理学与毒理学杂志》
CAS
CSCD
北大核心
1994年第2期83-86,共4页
Chinese Journal of Pharmacology and Toxicology
关键词
乙酰胆碱
氨基吡啶
镧
神经节
突触
acetylcholine
aminopyridines
lanthanum
ganglia, sympathetic
synapses
