Bartlett D, Knuth S L, Ward D K
Department of Physiology, Dartmouth Medical School, Hanover, NH 03756.
Respir Physiol. 1987 Nov;70(2):173-81. doi: 10.1016/0034-5687(87)90048-x.
Sedative drugs have been found to depress the respiratory activity of upper airway muscles more than that of the diaphragm. To determine whether CO2 at narcotic levels has a similar action, we recorded phrenic and hypoglossal nerve activities in decerebrate, vagotomized, paralyzed cats. T5 or T6 external intercostal nerve activity was also recorded in some animals. End-tidal CO2 concentration was raised progressively to over 30% or until depression of nerve activity was apparent. Respiratory frequency was reduced by severe hypercapnia in most cats. Hypoglossal nerve activity was consistently decreased more than that of the phrenic nerve. In most cases intercostal nerve activity was also more susceptible than phrenic nerve activity to hypercapnic depression. The results indicate that CO2 at narcotic levels interferes both with the central pattern generator for breathing movements and with the expression of the pattern in specific motor nerves.
已发现镇静药物对上呼吸道肌肉呼吸活动的抑制作用比对膈肌的抑制作用更强。为了确定麻醉水平的二氧化碳是否有类似作用，我们记录了去大脑、切断迷走神经、麻痹的猫的膈神经和舌下神经活动。在一些动物中还记录了第5或第6胸段肋间神经活动。呼气末二氧化碳浓度逐渐升高至超过30%或直至神经活动明显受抑制。大多数猫因严重高碳酸血症导致呼吸频率降低。舌下神经活动始终比膈神经活动减少得更多。在大多数情况下，肋间神经活动也比膈神经活动对高碳酸血症抑制更敏感。结果表明，麻醉水平的二氧化碳既干扰呼吸运动的中枢模式发生器，也干扰特定运动神经中模式的表达。
