Effects of acetylcholine (ACh) on respiratory activity have been an intriguing theme especially in relation to central chemoreception and the control of hypoglossal nerve activity. We studied the effects of ACh on hypoglossal and phrenic (C4) nerve activities and inspiratory and pre-inspiratory neurons in the rostral ventrolateral medulla in brainstem-spinal cord preparations from newborn rats. ACh application increased respiratory rhythm, decreased inspiratory hypoglossal and C4 nerve burst amplitude, and enhanced pre-inspiratory hypoglossal activity. ACh induced membrane depolarization of pre-inspiratory neurons that might be involved in facilitation of respiratory rhythm by ACh. Effects of ACh on hypoglossal and C4 nerve activity were partially reversed by a nicotinic receptor blocker, mecamylamine. Further application of a muscarinic receptor antagonist, oxybutynin, resulted in slight increase of hypoglossal (but not C4) burst amplitude. Thus, ACh induced different effects on hypoglossal and C4 nerve activity in the brainstem-spinal cord preparation.

乙酰胆碱 (ACh) 对呼吸活动的影响一直是一个有趣的主题，特别是与中枢化学感受和舌下神经活动的控制有关。我们研究了 ACh 对新生大鼠脑干脊髓制剂中舌下和膈 (C4) 神经活动以及延髓头端腹外侧神经元的吸气和吸气前神经元的影响。ACh 应用增加了呼吸节律，降低了吸气舌下和 C4 神经爆发幅度，并增强了吸气前舌下活动。ACh 诱导吸气前神经元的膜去极化，这可能与 ACh 促进呼吸节律有关。ACh 对舌下神经和 C4 神经活动的影响被烟碱样受体阻滞剂美加明部分逆转。毒蕈碱受体拮抗剂奥昔布宁的进一步应用导致舌下（但不是 C4）爆发幅度略有增加。因此，ACh 对脑干-脊髓准备中的舌下神经和 C4 神经活动有不同的影响。