对抗大鼠氟西泮抗癫癎耐受性药物及其机制的研究

Drugs and the mechanism for reversing the tolerance of flurazepan in rats

目的苯二氮卓类药物对各种癫癎均有疗效,长期应用容易产生耐受性,本实验目的是寻找逆转氟西泮抗痫耐受性的药物,探讨神经肽Y(NPY)在此过程中的作用。方法建立对氟西泮抗痫耐受性的大鼠模型。模型建立后,根据干预药物的种类分为7组:氟西泮耐受组(无药物干预)、硝苯地平组、左乙拉西坦组、托吡酯组、氟马西尼组、L-NAME组、维生素B6组。通过尾静脉注射戊四唑来检测其耐受性,记录其戊四唑致惊厥的潜伏期和惊厥阈值。运用免疫组化法检测海马中NPY表达,通过RT-PCR检测NPY2受体mRNA的改变。结果与空白对照组相比,氟西泮耐受组的潜伏期缩短、惊厥阈值降低,海马中神经肽Y表达、NPY2受体的mRNA减少。而逆转耐受性后,托吡酯组的潜伏期延长了2倍,惊厥阈值升高了2倍,硝苯地平、左乙拉西坦、氟马西尼组潜伏期延长了1倍,惊厥阈值升高了1倍。氟马西尼组、硝苯地平组和托吡酯组NPY2受体mRNA与氟西泮耐受组比较,增加了1～2倍,差异有显著性意义,P<0.01。结论硝苯地平、左乙拉西坦、托吡酯、氟马西尼能够逆转氟西泮抗癫癎的耐受性,NPY可能是介导其逆转耐受性因素之一。

Objective Benzodiazepines （BDZ） have many effects on various kinds of epilepsies, but long-term treatment with BDZ often leads to drug tolerance. This study aimed to seek drugs which can reverse the tolerance of flurazepam （FZP）, and to explore the role of neuropeptide Y （NPY） in the reversal effect. Methods A rat model of anticonvulsant tolerance to FZP was prepared. The rats with FZP tolerance were randomly assigned to seven groups： FZPtolerance, and nifedipine, levetiracetam, topiramate, flumazenil, L-NAME and pyridoxamine treatment groups. The tolerance to FZP was evaluated through pentylenetetrazol （PTZ） infusion into a tail vein. The latency to onset of clonic seizure and the PTZ threshold were recorded. The mRNA of NPY receptor Y2 in the hippocampus was determined by RT-PCR, and the distribution of NPY in the hippocampus was examined by immunohistochemistry. Results In comparison with the blank control group, the average latency to the onset of clonic seizure was shortened, the average PTZ threshold decreased and the expression of NYT and NPY receptor Y2 mRNA decreased significantly in the FZP-tolerance group （ P 〈 0.01 ）. In comparison with the FZP-tolerance group, the average latency to onset of clonic seizure was prolonged by 2 times and the average PTZ threshold doubled in the topiramate treatment group. The average latency to onset of clonic seizure was prolonged by 1 time and the average PTZ threshold increased 1 time in the nifedipine, the levetiracetam and the flumazenil treatment groups. The mRNA expression of NPY receptor Y2 increased by 1 or 2 times in the flumazenil, the nifedipine and the topiramate treatment groups when compared with the FZP-tolerance group. Conclusions Nifedipine, levetiracetam, topiramate and flumazenil can reverse the anticonvulsant tolerance to flurazepam. NPY may play a role in mediating the reversal effect.