P物质对大鼠星状神经节细胞的除极化

应用细胞内生物电记录技术,观察神经肽P物质(SP)对大鼠星状神经节细胞的影响.SP在1 μmol～10 μmol或更高的浓度范围内,供试35个细胞, 有28个细胞发生膜除极反应.用低钙(0.25 mm)或用含河豚毒素(TTX,1 μmol)克氏液灌流神经节,不影响SP引起的除极反应的幅度和时程.SP引起除极反应的同时常伴有膜电阻增大.当膜电位增大时,除极化反应幅度变小,反转电位为-80 mV至-100 mV.研究表明,SP对部分星状神经节细胞具有兴奋作用,使通过这些细胞的信息传递增强;SP对细胞膜的除极作用是由于其引起细胞膜钾导降低所致.

Depolarization Induced by Substance P on Rat Stellate Ganglion Neurons

The effects of neuropeptide substance P(SP) on the neurons of the isolated stellate ganglia of the rat were investigated by means of intracellular recording techniques.At the concentration of 1 μm to 10 μm,SP caused a low,monophersic depolarization in 28 out of 35 cells tested, low Ca2+ or tetrodotoxin (TTX)-containing Kreb's solution did not cause any significant change of the amplitude or duration of SP-induced depolarization.SP-induced depolarization was often associated with an increase in membrane resistance.Generally,the response was reversed on membrane potential of -80 mV to -100 mV.It is concluded that SP is excitatory to stellate ganglionic neurons and serves to augment impulse transmission through the neurons.These findings also suggest that a reduction of membrane K + conductance may underline the depolarization action of SP.