Wade P R, Wood J D
Department of Physiology, College of Medicine, Ohio State University, Columbus 43210.
Eur J Pharmacol. 1988 Mar 22;148(1):1-8. doi: 10.1016/0014-2999(88)90447-5.
Intracellular methods were used to study the effects of serotonin and substance P (SP) on the electrical behavior of myenteric neurons in guinea-pig distal colon in vitro. Serotonin evoked either a short-duration transient depolarization, a long-lasting depolarization or a multiphasic response consisting of a rapid depolarization followed by a short duration hyperpolarizing potential and then a long-lasting depolarization. Application of SP evoked a long-lasting depolarization. Depolarizing potentials to both substances were accompanied by enhanced excitability that was reflected by repetitive spike discharge. Long-lasting depolarizations were associated with increased input resistance. The responses to serotonin or SP were unaltered by the presence of tetrodotoxin, hexamethonium or elevated extracellular Mg2+ and reduced Ca2+. Some neurons responded to both serotonin and SP indicating that both receptors coexisted on the same neuron. The putative SP antagonist, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]SP did not affect the responses to SP. It did suppress the slow-depolarizing response to serotonin, while the fast response was unaffected. The responses to serotonin and SP in myenteric neurons of guinea-pig colon resembled the responses reported by others for small intestinal myenteric neurons.
采用细胞内记录方法，研究了5-羟色胺和P物质（SP）对豚鼠离体远端结肠肌间神经元电活动的影响。5-羟色胺可诱发短时程的瞬时去极化、长时程去极化或多相反应，后者包括快速去极化，随后是短暂的超极化电位，然后是长时程去极化。应用SP可诱发长时程去极化。两种物质引起的去极化电位均伴有兴奋性增强，表现为重复的锋电位发放。长时程去极化与输入电阻增加有关。5-羟色胺或SP引起的反应不受河豚毒素、六甲铵或细胞外Mg2+浓度升高及Ca2+浓度降低的影响。一些神经元对5-羟色胺和SP均有反应，表明两种受体共存于同一神经元上。假定的SP拮抗剂[D-Arg1，D-Phe5，D-Trp7,9，Leu11]SP不影响对SP的反应。它确实抑制了对5-羟色胺的慢去极化反应，而快速反应不受影响。豚鼠结肠肌间神经元对5-羟色胺和SP的反应与其他人报道的小肠肌间神经元的反应相似。
