Modulation of inwardly rectifying channels by substance P in cholinergic neurones from rat brain in culture.
Modulation of inwardly rectifying channels by substance P in cholinergic neurones from rat brain in culture.
复制标题
P物质对培养大鼠脑胆碱能神经元内向整流通道的调节。
DOI：
10.1113/jphysiol.1990.sp018151
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Stanfield,PR
中科院分区：
文献类型：
--
作者：
Yamaguchi,K;Nakajima,Y;Nakajima,S;Stanfield,PR
1.采用全细胞记录技术研究P物质对培养的大鼠基底核神经元的影响。2.简短的应用程序的P物质产生的减少，约1分钟的持续时间，静息膜电导。产生半数最大效应的浓度约为40 nM，P物质的持续存在导致反应脱敏。3.对照电流-电压关系在-70至-150 mV的电压范围内表现出内向整流，超极化导致电流呈时间依赖性降低（失活）。4.通过从对照电流中减去速激肽存在期间的电流获得的P物质敏感电流显示无时间依赖性失活，尽管其电流-电压关系也显示向内整流，其中逆转电位约等于钾平衡电位Vk。5.物质P敏感弦电导与电压之间的关系可以通过波尔兹曼方程来拟合，[K+]o的变化使该关系沿着电压轴移动，大致与Vk的移动平行。最大电导与[（K+）]o）成正比。6. Cs+（0.1 mM）以电压依赖性方式阻断P物质敏感电流，Cs+的等效化合价为1.9。P物质敏感电流的钡阻断具有较小的电压依赖性。7.用四甲基铵（TMA+）离子替代外部Na+，使P物质敏感电流仅降低18%。8.这些结果表明，P物质抑制钾通道的内向整流特性非常相似的骨骼肌。9.应用硝普钠并不改变P物质的作用，表明环GMP在通道调节中不起作用。
1. Whole‐cell recording was used to investigate the effects of substance P on cultured neurones from the rat nucleus basalis. 2. Brief applications of substance P produced a reduction, about 1 min in duration, of resting membrane conductance. The concentration producing a half‐maximal effect was approximately 40 nM, with the continuous presence of substance P resulting in desensitization of the response. 3. The control current‐voltage relation exhibited inward rectification over the voltage range ‐70 to ‐150 mV, and hyperpolarization produced a time‐dependent decrease of current (inactivation). 4. The substance P‐sensitive current, obtained by subtracting the current during the presence of the tachykinin from the control current, showed no time‐dependent inactivation, though its current‐voltage relation also revealed inward rectification, with the reversal potential being approximately equal to the potassium equilibrium potential, Vk. 5. The relation between the substance P‐sensitive chord conductance and voltage could be fitted by a Boltzmann equation, with changes in [K+]o shifting this relation along the voltage axis roughly in parallel with the shift in Vk. The maximum conductance was proportional to [( K+]o). 6. Cs+ (0.1 mM) blocked the substance P‐sensitive current in a voltage‐dependent manner, with an equivalent valency for Cs+ of 1.9. Barium blockage of the substance P‐sensitive current was less voltage dependent. 7. Replacement of external Na+ by tetramethylammonium (TMA+) ions reduced the substance P‐sensitive current by only 18%. 8. These results indicate that substance P inhibits potassium channels with inward rectifier properties very similar to those of skeletal muscle. 9. Application of sodium nitroprusside did not alter the effect of substance P, suggesting that cyclic GMP plays no role in the channel modulation.