Sugisawa K, Komori S, Takewaki T, Ohashi H
Department of Veterinary Science, Faculty of Agriculture, Gifu University, Japan.
Jpn J Pharmacol. 1991 Nov;57(3):279-89. doi: 10.1254/jjp.57.279.
Intestinal segments obtained from guinea pig ileum were set up in an organ bath to record peristaltic responses to distension by a pressure rise in the lumen. The effects of drugs applied in the bathing medium on the peristaltic responses were examined. Sodium nitroprusside (10(-9) M to 10(-5) M) stimulated the peristaltic reflex. Nitroglycerin (10(-7) M) was similarly effective in stimulating the peristalsis. A permeable cyclic GMP, 8-bromo cyclic GMP (2.5 x 10(-4) M), mimicked the action of these compounds. Methylene blue (10(-5) M) blocked the nitroprusside-induced stimulation of the peristalsis, but not the effect of 8-bromo cyclic GMP. Sodium nitroprusside did not change the baseline tension of the circular muscle, and it enhanced neither the contractile response to electrical direct stimulation nor the cholinergic transmission to the circular muscle. These results suggest that nitric oxide is formed from the nitrocompounds in mechanosensitive neurons in the intestine and causes activation of guanylate cyclase by which the level of intracellular cyclic GMP is elevated, and cyclic GMP acts to make the stretch receptors more sensitive. As nitric oxide is derived from the enteric vascular bed or neurons, its importance as a modulator of peristaltic activity in the intestine is discussed.
从豚鼠回肠获取肠段，将其置于器官浴槽中，通过肠腔内压力升高来记录对扩张的蠕动反应。检测浴液中所加药物对蠕动反应的影响。硝普钠（10⁻⁹M至10⁻⁵M）刺激蠕动反射。硝酸甘油（10⁻⁷M）在刺激蠕动方面同样有效。一种可渗透的环磷酸鸟苷，8-溴环磷酸鸟苷（2.5×10⁻⁴M），模拟了这些化合物的作用。亚甲蓝（10⁻⁵M）阻断了硝普钠诱导的蠕动刺激，但不影响8-溴环磷酸鸟苷的作用。硝普钠不改变环行肌的基础张力，既不增强对电直接刺激的收缩反应，也不增强向环行肌的胆碱能传递。这些结果表明，一氧化氮由肠道机械敏感神经元中的硝基化合物形成，并导致鸟苷酸环化酶激活，从而使细胞内环磷酸鸟苷水平升高，环磷酸鸟苷作用于使牵张感受器更敏感。由于一氧化氮来源于肠道血管床或神经元，因此讨论了其作为肠道蠕动活动调节剂的重要性。
