Niel J P, Bywater R A, Taylor G S
J Auton Nerv Syst. 1983 Dec;9(4):573-84. doi: 10.1016/0165-1838(83)90114-5.
Membrane potentials were recorded with intracellular electrodes from the circular muscle cells of the guinea-pig ileum, in vitro, in the presence of atropine (1.4 X 10(-6) M) at 30 degrees C. Under such conditions, the preparations did not show any spontaneous activity. Exposure of the tissue to substance P (10(-7)-10(-6)M) for a short period of time (less than 5 min) caused depolarization and action potentials. At this time the membrane resistance appeared to be decreased and after transmural nerve stimulation the fast post-stimulus depolarization, which followed the inhibitory junction potential (IJP), triggered action potentials. After prolonged exposure of the tissue to substance P (greater than 10 min), the contractile activity of the preparation subsided, the membrane potential was decreased by 6.4 +/- 1.1 mV and the membrane resistance was increased; following transmural nerve stimulation, the amplitude of the IJP was increased, the fast post-stimulus depolarization was abolished and the later slow post-stimulus depolarization was enhanced and in some preparations reached threshold for action potential generation. In the latter preparations in the absence of transmural nerve stimulation, the membrane potential occasionally showed regular oscillations of approximately 10 mV in amplitude every 5-8 s. When the tissue was hyperpolarized by anodal current, after prolonged exposure to substance P, the fast post-stimulus depolarization did not return indicating that its abolition was not a secondary effect due to the depolarization of the tissue by substance P.
在30℃下，于体外，在存在阿托品（1.4×10⁻⁶M）的情况下，用细胞内电极记录豚鼠回肠环行肌细胞的膜电位。在这种条件下，制备物未表现出任何自发活动。将组织短时间（少于5分钟）暴露于P物质（10⁻⁷ - 10⁻⁶M）会引起去极化和动作电位。此时膜电阻似乎降低，经壁神经刺激后，跟随抑制性接头电位（IJP）的快速刺激后去极化引发动作电位。在组织长时间暴露于P物质（大于10分钟）后，制备物的收缩活动减弱，膜电位降低6.4±1.1mV，膜电阻增加；经壁神经刺激后，IJP的幅度增加，快速刺激后去极化消失，后期缓慢刺激后去极化增强，在一些制备物中达到动作电位产生阈值。在无经壁神经刺激的后一种制备物中，膜电位偶尔显示出幅度约为10mV、每隔5 - 8秒的规则振荡。当组织通过阳极电流超极化时，在长时间暴露于P物质后，快速刺激后去极化不再恢复，表明其消失不是由于P物质使组织去极化引起的继发效应。
