摘要
目的:观察P物质(SP)对神经元H+门控电流的调制作用及其可能存在的机制。方法:采用全细胞膜片钳技术分别记录pH 4.0、pH 5.0、pH 6.0及共加H+与SP情况下,急性分离的大鼠背根神经节(DRG)神经元H+门控电流的形式。通过胞内透析技术分析SP对H+门控电流可能的调控机制。结果:H+门控电流可划分为短暂内流型(T型)、持续内向电流型(S型)、反向电流型(O型)及双相内向电流型(B型)。SP对S型和B型中持续成分的H+门控电流有明显增强作用,这种电流幅值增强达(85.53±22.93)%,约81.8%细胞的这种增强效应不能被选择性的SP受体NK1拮抗剂阻断,而非肽类的SP受体NK1拮抗剂对约75%的DRG神经元可明显阻断这种增强效应;SP对S型和B型中持续成分的H+门控电流也有明显抑制作用,抑制的幅值达(48.46±4.45)%,并且约88.9%细胞的这种抑制效应不能被SP受体NK1拮抗剂所阻断。通过胞内透析技术在细胞内液中加入GDP-β-S后不能消除SP对H+门控电流的调制作用。结论:H+门控电流有T型、S型、O型及B型4种电流类型。SP对H+门控电流有增强和抑制的双向调节作用。SP可能通过G蛋白偶联受体通路及与H+门控离子通道的某一位点直接结合来发挥对H+门控电流的双向调节调制作用。
AIM： To investigate the effects of substance P （SP） on the modulation of H^＋-gated current in neurons. METHODS： Whale-cell patch-clamp technique was used to record the H^＋ -gated current in the acutely isolated rat dorsal root ganglion （DRG） neurons at pH 4.0, pH 5.0, pH 6.0, and both SP and H^＋. The modulating action of SP on H^＋ -gated Current in the acutely isolated rat DRG neurons was studied by intracellular dialysis. RESULTS： H^＋ -gated currents recorded at pH 5.0 were divided into 4 types： transient inward （T-type）, sustained inward （S-type）, biphasic inward （B-type） and opposite （O-type）. SP exhibited obvious enhancing effect on the sustained component of S-type and B-type H^＋ -gated currents, and the enhancing current amplitude was （85.53 ±22.93 ）%. However, the enhancing effect was not blocked by the SP receptor NK1 antagonist in about 81.8% DRG neurons. The enhancing effect was blocked by nonpeptidic SP receptor antagonist in about 75% DRG neurons. SP also exhibited obvious inhibitory effect on the sustained component of S-type and B-type H^＋ -gated currents, and the inhibitory current amplitude was （48.46 ±4.45） %. However, the inhibitory effect was not blocked by the SP receptor antagonist in about 88.9% DRG neurons. After intracellular dialysis, GDP-β-S could not block the modulating action of SP on H^＋ -gated currents. CONCLUSION： There are 4 types of H^＋ -gated currents in acutely isolated rat DRG neurons ： T-type, S-type, B-type and O-type. The modulating action of SP on H^＋ -gated current exhibits both enhancement and inhibition. The regulatory mechanism includes G-protein-coupled receptor pathway and the binding of SP to a locus of H^＋ -gated ion channels to exert modulating action on the H^＋ -gated current.
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2014年第5期847-852,共6页
Chinese Journal of Pathophysiology
关键词
全细胞膜片钳术
H^+门控电流
P物质
胞内透析
Whole-cell patch-clamp techniques
H ^＋ -gated current
Substance P
Intracellular dialysis
