Jin J G, Neya T, Takaki M
Department of Physiology, Okayama University Medical School, Japan.
Acta Med Okayama. 1988 Jun;42(3):129-36. doi: 10.18926/AMO/31027.
To study the polarity of the efferent pathway of the myenteric plexus, recordings were made of the mechanical activity of the longitudinal muscle of isolated guinea-pig ileal segments upon stimulation with an electrical field around the myenteric plexus contained within strips of longitudinal muscle (LM-MP) continuous with each end of ileal segment. The amplitude of the contractile response to stimulation of the anal LM-MP was always larger than that to the oral LM-MP. After cholinergic and adrenergic transmission was suppressed by atropine (10 microM) and guanethidine (1 microM), and the tone of the segment was enhanced by histamine (1 microM), the LM-MP stimulation produced non-cholinergic, non-adrenergic (NCNA) ascending contraction and NCNA descending relaxation. The NCNA contraction, but not the NCNA relaxation, was abolished or reduced by desensitization to substance P. The present results suggest that the NCNA innervation of the myenteric plexus participates in the polar effects observed in the guinea-pig ileum, that the NCNA excitatory response may be mediated at least in part by myenteric substance P neurons, and that the NCNA inhibitory response is mediated by non-adrenergic neurons.
为研究肠肌丛传出通路的极性，在与豚鼠回肠段两端相连的纵行肌条（LM-MP）内，用围绕肠肌丛的电场刺激，记录离体豚鼠回肠段纵行肌的机械活动。刺激肛门侧LM-MP引起的收缩反应幅度总是大于刺激口腔侧LM-MP。在用阿托品（10微摩尔）和胍乙啶（1微摩尔）抑制胆碱能和肾上腺素能传递，并通过组胺（1微摩尔）增强肠段张力后，刺激LM-MP产生非胆碱能、非肾上腺素能（NCNA）的上行收缩和NCNA下行舒张。对P物质脱敏可消除或减弱NCNA收缩，但不能消除或减弱NCNA舒张。本研究结果提示，肠肌丛的NCNA神经支配参与了豚鼠回肠中观察到的极性效应，NCNA兴奋性反应可能至少部分由肠肌P物质神经元介导，而NCNA抑制性反应由非肾上腺素能神经元介导。
