COMPARISON OF THE CAPSAICIN-SENSITIVITY AND AMINO ACID-SENSITIVITY OF DORSAL-ROOT C-FIBERS IN THE RAT AND THE TOAD
COMPARISON OF THE CAPSAICIN-SENSITIVITY AND AMINO ACID-SENSITIVITY OF DORSAL-ROOT C-FIBERS IN THE RAT AND THE TOAD
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DOI：
10.1016/0742-8413(91)90279-3
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发表时间：
1991-01-01
期刊：
影响因子：
--
通讯作者：
EVANS, RH
中科院分区：
文献类型：
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作者：
HAWKINS, NS;HEARN, J;EVANS, RH
1. 在25 ℃和10 ℃下分别用大鼠和蟾蜍背根的抽吸电极记录复合动作电位（CAP）的C升高。 在大鼠和蟾蜍神经中，C纤维CAP的传导速度分别为0.5 ± 0.07 SE M/sec（N = 10）和0.25 ± 0.04 M/sec（N = 8）. 测定了药物对C纤维CAP振幅的抑制作用。 两种动物的神经对GABA的敏感性相似。 大鼠和蟾蜍的EC 50分别为5.0-mu-M +/- 0.5 SEM（N = 3）和5.5-mu-M +/- 1.4（N = 3）。 GABA在大鼠和蟾蜍神经中产生的最大抑制作用分别为35% +/- 5 SEM和17% +/- 2.5 SEM。 在十个测试的大鼠神经中的五个中，红藻氨酸盐对C纤维CAP具有明显的抑制作用（最大36% +/-4.3SEM，EC 50 6.8-μ-M +/-0.9SEM，N = 3）。 浓度从100到500 μ M的红藻氨酸对七条蟾蜍神经没有影响。 蟾蜍神经对辣椒素的敏感性比大鼠神经低约100倍（ED 50值分别为430 μ M +/-190 SEM和0.7 μ M +/-0.2，N = 4）。 在这两个物种的GABA和不同的敏感性红藻氨酸和辣椒素的神经的敏感性相似，表明两栖类C纤维特别缺乏敏感性辣椒素和红藻氨酸。
1. The C elevation of the compound action potential (CAP) was recorded with suction electrodes from dorsal roots of rats at 25-degrees-C and toads (Bufo bufo) at 10-degrees-C. The C fibre CAP had a conduction velocity of 0.5 +/- 0.07 SE M per sec (N = 10) and 0.25 +/- 0.04 M per sec (N = 8) in the rat and toad nerves respectively.2. The depressant effect of applied drugs on the amplitude of the C fibres CAP was measured. Nerves from both species had similar sensitivities to GABA. EC50 5.0-mu-M +/- 0.5 SEM (N = 3) and 5.5-mu-M +/- 1.4 (N = 3) for the rat and toad respectively. Maximum depressant effects of GABA produced in rat and toad nerves were 35% +/- 5 SEM and 17% +/- 2.5 respectively.3. In five out of ten of the rat nerves tested kainate had a clear depressant effect (maximum 36% +/- 4.3 SEM, EC50 6.8-mu-M +/- 0.9 SEM, N = 3) on the C fibre CAP. Kainate, at concentrations from 100 to 500-mu-M, had no effect on seven toad nerves.4. Toad nerves were about 100 times less sensitive, than rat nerves, to capsaicin (ED50 values 430-mu-M +/- 190 SEM and 0.7-mu-M +/- 0.2 respectively, N = 4).5. The similar sensitivity of nerves in both species to GABA and differing sensitivies to kainate and capsaicin suggests that amphibian C fibres specifically lack sensitivity to capsaicin and kainate.