河豚毒素对电刺激诱发的兔隐动脉双相血管收缩反应的作用  

Effects of tetrodotoxin on biphasic vasoconstrictive responses to electric stimulation in rabbit saphenous artery

作　　者：师晨霞[1] 任雷鸣[1] 李军霞[1] 

机构地区：[1]河北医科大学药学院药理学研究室,河北石家庄050017

出　　处：《中国药理学通报》2005年第9期1123-1127,共5页Chinese Pharmacological Bulletin

基　　金：河北省自然科学基金资助项目(No302481)

摘　　要：目的采用兔离体隐动脉环标本,建立了双相血管收缩反应模型,并分析TTX(1～100 nmol·L-1)对两种收缩成分的影响.方法兔离体隐动脉血管环张力记录法及电场刺激诱发血管收缩法.结果本实验条件下的电场刺激(电压15 V、波宽1 ms、刺激频率2～16 Hz,连续刺激时程32 s)可诱发兔离体隐动脉产生双相收缩反应,且具有频率(2～16Hz)依赖性.钠通道选择性阻滞剂TTX 3 nmol·L-1 对第一相收缩反应无影响,但是明显抑制第二相收缩反应,抑制率达44%～67%;TTX的浓度增加至10 nmol·L-1时,其对4～16 Hz电刺激诱发的第一相反应的抑制率为40%～57% ,而对第二相反应的抑制率达90%以上.TTX (0.1 μmol·L-1)对NA(0.01～30 μmol·L-1)的累积量效曲线无任何影响,但是完全抑制了电刺激诱发的动脉环双相收缩反应.胍乙啶(10 μmol·L-1)完全抑制电刺激诱发的双相收缩反应,但是不抑制外源性NA的收缩反应.结论建立了电场刺激诱发兔离体隐动脉环双相收缩反应模型,该双相收缩与交感神经兴奋及其递质的释放有关.Abstract：Aim To establish a model of biphasic vasoconstriction induced by electrical stimulation, and analyze effects of 1 - 100 nmol·L^-1 tetrodotoxin （TTX） on the biphasic vasoconstriction in the ring preparation of the rabbit saphenous artery. Methods Isometric vasoconstriction of the rabbit saphenous arterial rings was recorded, and the sympathetic nerves of the arterial rings were activated with electrical stimulation. Resuits The biphasic neurogenic vasoconstriction was consistently induced by electrical stimulation （15 V, 1 ms pulse duration,2 - 16 Hz for 32 s） in a frequency- related manner in the rabbit saphenous artery. TTX （3 nmol·L^-1）, a neuronally selective sodium channel blocker, did not affect the first phase of vasoconstriction, but it markedly inhibited the second phase of vasoconstrictive responses to 2 - 16 Hz stimulation by 44 % -67 %. Increasing the concentration of TTX to 10 nmol·L^-1,TTX inhibited the first phase of the vasocontractive responses to 4 - 16 Hz stimulation by 40%- 57%, whereas it inhibited more than 90% of the second phase of vasoconstriction. Concentration-response curves for NA（0. 01 -30 μmol·L^-1） were not affected by TTX （0. 1μmol·L^-1 ）, but the same concentration of TTX completely inhibited the biphasic vascular responses to electrical stimulation. The biphasic contractile responses to electrical stimulation were all abolished by guanethidine （ 10μmol·L^-1 ） , but the vasoconstrictive responses to exogenous NA were not affected by it. Conclusion Biphasic vasoconstriction can be induced by electrical stimulation, and the first and the second phases of vasoconstriction are mediated by neurotransmitters released from sympathetic nerves in the rabbit isolated saphenous arterial ring preparation.

关 键 词：共递质 交感神经 电场刺激 河豚毒素 双相血管收 缩 兔隐动脉 

分 类 号：R-332[医药卫生] R322.121