速激肽受体介导的背根节辣椒素敏感的神经元膜电流的变化  

Tachykinin Receptors-Mediated Changes of Membrane Current in Capsaicin-senective Neurons in Adult Rat Dorsal Root Ganglion

作　　者：王过渡[1] 赵志奇[1] 

机构地区：[1]中国科学院上海脑研究所,上海200031

出　　处：《三峡大学学报（人文社会科学版）》1998年第1期83-93,共11页Journal of China Three Gorges University(Humanities & Social Sciences)

摘　　要：全细胞电压钳记录急性分离的成年大鼠背根节（dorsalrootganglion，DRG）神经元胞体通道电流．选择对辣椒素（capsaicin）敏感的神经元，0．2nM－1μmol/L的速激肽（tachykinins，TK），包括P物质（SP）、神经激肽A（NKA）、神经激肽B（NKB）灌流记录细胞，结果表明：TK能增大电压门控的Ca2+电流和河豚毒（TTX）不敏感的Na+电流，对电压依赖的外向K+电流呈加大和减少的双向反应；在静息膜电位水平，TK引起三种反应形式的内向电流：1）快速内向流；2）缓慢内向流；3）长时程振荡性内向流．三种速激肽受体的选择性桔抗剂能翻转TK引起的这些电流变化，用含有TK的无Ca2+或含Cd2+的外液灌流细胞，TK不再引起电压门控Ca2+电流增加。含TEA和Cs+的外液，对TK在静息膜电位水平引起的快速和缓慢内向流无明显作用；但在长时程振荡性内向流的基础上，引起一种可逆的快速内向流．含有TTX与用氯化胆硷置代NaCl的外液，或用Cd2+置代Ca2+的外液能明显减少这三种内向流，含TTX和Cd2+的外液则能几乎完全抑制它们．辣椒素敏感的DRG神经元对重复应用TK出现明显的脱敏现象．在静息膜电位水平，阿片肽能翻转速激肽引起的内向电流．DAMGO还能桔抗Sar－SP增大电压门控Ca2+电流的作用．The membrane channel currents were studied using whole cell voltage clamp in capsaicin-sensitive neurons isolated from adult rat dorsal root gangla. When tachykinins(100nmol/L),such as [Sar9, Met(02)11 ] SP (Sar-SP). neurokinin A(NKA) and neurokinin B(NKB), were usedfor perfusing the recording neurons, all the peptides increased voltage gated-Ca2+ current andtetrodotoxin (TTX) insensitive Na2 + current, and induced a biphasic effects on voltage gated - K+ outward current. At the resting membrane potential, tachykinins activated inwnd currentS have beencharacterics to three different types: fast, slow and long term oscillatory responses. All tachykinin induced responses weres blocked by selective tachykinin receptors antagnistsm , respectively.Tachykinins failed to induce the increase of voltage gated- Ca2 + current during application of perfusingsolution with free Ca2+ and Cd2+ instead Of Ca2+. Although tachykinins activated the inward currentswere not affected by the solution containing tetraethylammoium (TEA) and Cs+, but a fast reversibleinward current elicited additionally by the solution on the level of long term oscillatory current. Thethree inward currents were reduced with perfusing solution containing TTX and choine chioride substitute for NaCl. or octonal and Cd2+ substittute for Ca2+. However, the three currents were almost completely inhibited by bath medium maintaining TTX and Cd2+. Repetitive application of tachykininsproduced an apparent desensitization in the capsaicin sensitive neurons. Opioid peptides, DAMGO andDPDPE blocked tachykinins-induced inward current at resting membrane potential level. Also,DAMGO suppressed Sar -SP-enhanced higher threshold and voltage gated- Ca2+ current The rolesof DAMGO could he reversed by its selective antagonist, β- FNA.These results suggested that NK1, NK2 and NK3 receptors mediated tachykinin-induced currentsin cellular membranes of capsaicin sensitive neurons; Opening Na+, Ca2+ and nonselective cationchannels were involved in TK-induced mind currents. Tac

关 键 词：速激肽 背根节神经元 辣椒素 通道电流 全细胞电压钳 

分 类 号：R338[医药卫生—人体生理学]