Dalziel H H, Thornbury K D, Ward S M, Sanders K M
Department of Pharmacology, University of Nevada School of Medicine, Reno 89557.
Am J Physiol. 1991 May;260(5 Pt 1):G789-92. doi: 10.1152/ajpgi.1991.260.5.G789.
Experiments were performed to determine the involvement of nitric oxide synthase in the generation of nonadrenergic, noncholinergic (NANC) inhibitory junction potentials (IJPs) in the canine proximal colon. Smooth muscle cells were impaled near the myenteric border between the circular and longitudinal layers. Cells exhibited rhythmic myenteric potential oscillations. IJPs were evoked with electrical field stimulation in the presence of drugs to block adrenergic and cholinergic neurotransmission. N omega-nitro-L-arginine, methyl ester (L-NAME), a nitric oxide synthase inhibitor, progressively reduced the amplitude of IJPs. The effect of L-NAME was reversed by L-Arg but not by the stereoisomer D-Arg. IJPs disrupt the regular pattern of myenteric potential oscillations. This effect was also blocked by L-NAME and reversed by L-Arg. These experiments suggest that a product of the nitric oxide synthetic pathway is involved in NANC neurotransmission in the canine proximal colon.
进行实验以确定一氧化氮合酶在犬近端结肠非肾上腺素能、非胆碱能（NANC）抑制性接头电位（IJP）产生中的作用。在环形肌层和纵行肌层之间的肌间边界附近刺入平滑肌细胞。细胞表现出有节律的肌间电位振荡。在存在阻断肾上腺素能和胆碱能神经传递的药物的情况下，用电场刺激诱发IJP。一氧化氮合酶抑制剂Nω-硝基-L-精氨酸甲酯（L-NAME）逐渐降低IJP的幅度。L-精氨酸可逆转L-NAME的作用，而其立体异构体D-精氨酸则不能。IJP扰乱肌间电位振荡的正常模式。这种作用也被L-NAME阻断，并被L-精氨酸逆转。这些实验表明，一氧化氮合成途径的一种产物参与犬近端结肠的NANC神经传递。
