【摘要】 采用全细胞膜片钳技术研究了大鼠三叉神经节(trigeminal ganglion,TG)神经元膜P2X嘌呤受体的特征。结果发现: 大部分受检细胞(78．9％,142／180)对ATP敏感,ATP-激活电流有明显的浓度依赖性。少数细胞无反应(21．1％,38／180)。在对ATP敏感的142个细胞中,绝大部分引起一内向电流(95．1％,135／142),少数为外向电流(2．1％,3／142),另有部分细胞出现双相电流(2．8％,4／142)。引起的内向电流在小直径细胞(<30μm)上多表现为快去敏感电流,对vanilloid高度敏感;在中等大小的细胞(30-40 μm)上多表现为慢去敏感电流,对vanilloid不敏感;绝大多数大细胞(>40 μm)对ATP和vanilloid均不敏感。此外,电流的波形与细胞直径密切相关。无论小细胞还是中等细胞其I-V曲线均表现出明显的内向整流趋势。我们还研究了ATP-激活电流的动力学特征,并观察了P2嘌呤受体激动剂、拮抗剂的效应。结果提示:不同类型的ATP受体- 离子通道在不同类型的TG神经元上的表达具有不同的特点。更多还原

【Abstract】 The characteristics of purinoceptors in the membrane of rat trigeminal ganglion (TO) neurons were studied by using whole-cell patch clamp technique. The results showed that most of neurons examined (78.9%, 142/180) were responsive to ATP in a concentration-dependent manner; the others (21.1%, 38/180) were ATP insensitive. Of the ATP-sensitive cells, the majority (95.1%, 135/142) responded to ATP with an inward current, a few (2.1%, 3/142) with an outward current, and the rest (2.8%, 4/142) with biphasic current. Small sized cells (<30 μm) responded to ATP with a rapid desensitizing inward current and were highly sensitive to vanilloid; the medium sized cells (30-40 μm) responded to ATP with slow desensitizing inward current and were not sensitive to vanilloid; while the majority of large sized cells (>40 μm) did not respond to ATP and vanilloid. The waveform of ATP-activated inward currents was related to the cell diameter. The I-V curves for both small and medium sized cells manifested obvious inward rectification. Furthermore, we studied the kinetic features of ATP-activated currents and the effects of P2 purinoceptor agonists and antagonists on IATP.. The findings suggest that ATP receptor-ion channels are expressed differently among different types of rat TG neurons.更多还原