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蝎毒耐热蛋白对大鼠急性分离海马神经元兴奋性的影响

王越, 张晓芸, 李韶, 张健, 赵杰, 张万琴

大连医科大学生理学教研室,脑疾病研究所.辽宁,大连 116027

摘要

应用全细胞膜片钳记录技术在电流钳模式下观察经持续高温等特殊处理后分离纯化的30---50kDa蝎毒耐热蛋白（scorpion venom heat resistant protein。SVHRP）（国家发明专利，专利号ZL01 1 06166.92）对急性分离大鼠海马神经元兴奋性的影响。结果发现SVHRP可致海马神经元兴奋性降低。神经元经1×10~(-2)#mu#g／mLSVHRP处理后动作电位发放模式改变，发放频率减少。在52个受检细胞中，有45个细胞产生位相放电（占86.54％）；7个细胞产生重复放电（占13.46％）。在产生位相放电的45个细胞中，有8个细胞在SVHRP处理后仍可以诱发出位相放电（占17.78％）；37个细胞在SVHRP处理后无法诱导出位相放电（占82.22％），SVHRP处理后动作电位的产生与处理前相比，有显著差异（{sl P}<0.01，n=45）；在产生重复放电的7个细胞中，在1×10~(-2)#mu#g／mLSVHRP作用后均不能再次诱发出重复放电，而是产生一个动作电位或不再产生动作电位，药物处理前产生的动作电位个数为14.57±1.00，SVHRP处理后产生动作电位的个数为0.57±0.20，二者之间有显著性差异（{sl P}<0.01，n=7）。1×10~(-4)#mu#g／mLSVHRP处理后，诱发动作电位产生的基强度由（75.10±8.99）pA增加到（119.85±12.73）pA（{sl P}<0.01，n=8）；阈电位由（01.17±2.15）mV升至（--32.40±1.48）mV（{sl P}<0.01,n=8）；动作电位峰值由（68.49±2.33）mV下降至（54.71±0.81）mV（{sl P}<0.01，n=8）。由于神经元超兴奋性被认为是癫痫发作的基本机制之一，因此上述结果表明SVHRP有可能通过降低海马神经元兴奋性发挥其抗癫痫作用，这为蝎毒药物的进一步开发提供理论依据。

关键词： 蝎毒耐热蛋白; 全细胞膜片钳技术; 兴奋性; 海马神经元

Inhibitory effects of scorpion venom heat resistant protein on the excitability of acutely isolated rat hippocampal neurons

Wang Yue, Zhang Xiaoyun, Li Shao, Zhang Jian, Zhao Jie, Zhang Wanqin

Department of Physiology, Institute for Brain Disorder, Dalian Medical University.Dalian 116027,Liaoning

Abstract

The effects of scorpion venom heat resistant protein （SVHRP） （National invention patent of China, 2004-10-20, No. ZL01 1 06166.92） on the excitability of acutely isolated rat hippocampal neurons were observed by whole-cell recording and the potential molecular mechanisms underlying its antiepileptic effect were investigated further. The results showed that SVHRP could decrease the excitability of hippocampal neurons. SVHRP （1×10~(-2)#mu#g/mL） altered the action potential （AP） fwing mode and decreased the AP fwing frequency. Out of 52 neurons observed, 45 （86.54%） generated phasic firing, and 7 （13.46%） generated repetitive firing. Among the 45 neurons generating phasic firing, 8 （17.78%） neurons could still be induced phasic firing after treatment with 1×10~(-2)#mu#g/mL SVHRP and 37 （82.22%） neurons had no responses to the stimulation. The AP firing of neurons was dramatically different after treatment with SVHRP （P〈0.01, n=45）. Among the 7 repetitive firing neurons, all of them could only generate 1 or 0 AP instead of repetitive firing when SVHRP was applied. The number of Alas was 14.57±1.00 and 0.57±0.20 before and after SVHRP treatment （P〈0.01, n=7）. The AP rheobase was （75.10±8.99） pA and （119.85±12.73） pA before and after 1×10~(-4)#mu#g/mL SVHRP application, respectively （P〈0.01, n=8）. The AP threshold was increased from （-41.17±2.15） mV to （-32.40±1.48） mV after 1×10~(-4)#mu#g/mL SVHRP treatment （P〈0.01, n=8）. The peak amplitude of AP was （68.49±2.33） mV for the neurons before treatment with 1×10~(-4)#mu#g/mL SVHRP and （54.71±0.81）mV after treatment （P〈0.01, n=8）. These results showed that SVHRP could decrease the AP firing frequency, increase the AP rheobase and threshold, but decrease the AP peak amplitude of hippocampal neurons. In other words, SVHRP can decrease the excitability of hippocampal neurons. SVHRP probably alters the excitability of hippocampal neurons by affecting sodium channels and this may be one of the underlying molecular mechanisms for its antiepileptic effect.

Key words: scorpion venom heat resistant protein;whole-cell patch clamp;Excitability;Hippocampal neuron

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引用本文：

王越, 张晓芸, 李韶, 张健, 赵杰, 张万琴. 蝎毒耐热蛋白对大鼠急性分离海马神经元兴奋性的影响[J]. 生理学报 2007; 59 (1): 87-93.

Wang Yue, Zhang Xiaoyun, Li Shao, Zhang Jian, Zhao Jie, Zhang Wanqin. Inhibitory effects of scorpion venom heat resistant protein on the excitability of acutely isolated rat hippocampal neurons. Acta Physiol Sin 2007; 59 (1): 87-93 (in Chinese with English abstract).