Peever J H, Mateika J H, Duffin J
Departments of Physiology and Anaesthesia, University of Toronto, Toronto, Ontario, Canada, M5S 1A8.
Pflugers Arch. 2001 Apr;442(1):78-86. doi: 10.1007/s004240000502.
In this study of adult and neonatal rats, we used cross-correlation analysis to detect synchronous neuronal events in hypoglossal and phrenic nerves to infer synaptic connections. We found evidence for the common excitation of medial and lateral hypoglossal motoneurones in 12 anaesthetized adult rats but not in 6 in vitro brainstem-spinal cord preparations. We did not find evidence for the common activation of phrenic and hypoglossal motoneurones in 23 adult and 10 neonatal rat preparations. We confirmed this negative result by demonstrating that 26 medullary inspiratory neurones activating phrenic motoneurones did not activate hypoglossal motoneurones in 23 adult decerebrate rats (except in one case). We also found that 15 Bötzinger expiratory neurones inhibiting phrenic motoneurones did not inhibit hypoglossal motoneurones. We conclude that: (1) motoneurones of the medial and lateral hypoglossal nerve branches receive inspiratory drive from a common premotor population in adult rats, but in neonatal rats adjacent nerve rootlets do not; (2) in both adult and neonatal rats phrenic premotor neurones do not monosynaptically excite hypoglossal motoneurones; (3) Bötzinger expiratory neurones that inhibit phrenic motoneurones do not inhibit hypoglossal motoneurones. We therefore suggest that the respiratory control of hypoglossal motoneurones is separate from that of phrenic motoneurones.
在这项针对成年和新生大鼠的研究中，我们使用互相关分析来检测舌下神经和膈神经中的同步神经元事件，以推断突触连接。我们发现，在12只麻醉的成年大鼠中，有证据表明舌下神经内侧和外侧运动神经元存在共同兴奋，但在6个体外脑干 - 脊髓标本中未发现。在23个成年大鼠和10个新生大鼠标本中，我们没有找到膈神经和舌下神经运动神经元共同激活的证据。我们通过证明在23只成年去大脑大鼠中，26个激活膈神经运动神经元的延髓吸气神经元并未激活舌下神经运动神经元（只有一例除外），证实了这一阴性结果。我们还发现，15个抑制膈神经运动神经元的包钦格复合体呼气神经元并未抑制舌下神经运动神经元。我们得出以下结论：（1）成年大鼠舌下神经分支的运动神经元从共同的运动前神经元群接收吸气驱动，但新生大鼠相邻神经根则不然；（2）在成年和新生大鼠中，膈神经运动前神经元均不会单突触兴奋舌下神经运动神经元；（3）抑制膈神经运动神经元的包钦格复合体呼气神经元不会抑制舌下神经运动神经元。因此，我们认为舌下神经运动神经元的呼吸控制与膈神经运动神经元的呼吸控制是分开的。
