Huang Q, Zhou D, St John W M
Department of Physiology, Dartmouth Medical School, Lebanon, New Hampshire 03756.
J Appl Physiol (1985). 1993 Apr;74(4):1934-40. doi: 10.1152/jappl.1993.74.4.1934.
Expiratory-related activities of spinal nerves are augmented after stimulation of the infracerebellar nucleus of the cerebellum. These stimulations alter neither inspiratory spinal neural activities nor inspiratory and expiratory laryngeal neural activities. It was hypothesized that efferents from the infracerebellar nucleus impinge on spinal motoneurons by a pathway that bypasses the medulla. In decerebrate, paralyzed, and vagotomized cats, phrenic and expiratory triangularis sterni activities and activities of medullary respiratory neurons were recorded. During infracerebellar stimulation, activities increased for expiratory bulbospinal neurons and neurons with tonic discharge patterns. After unilateral ablation of the infracerebellar nucleus by kainic acid, triangularis sterni discharge was eliminated and activities of expiratory bulbospinal neurons continued at reduced frequencies. Stimulations of the anterior interposed nucleus caused both inspiratory and expiratory activities to increase, whereas no systematic changes followed stimulations of the vermis. Results establish that at least a portion of the changes in expiratory activities of spinal motoneurons after perturbations of the infracerebellar nucleus occurs secondarily to changes in activities of medullary neurons. The possibility of separate cerebellar projections to medullary and spinal neurons is discussed.
刺激小脑下核后，脊髓神经的呼气相关活动增强。这些刺激既不改变吸气性脊髓神经活动，也不改变吸气和呼气性喉神经活动。据推测，小脑下核的传出神经通过一条绕过延髓的通路作用于脊髓运动神经元。在去大脑、麻痹和切断迷走神经的猫身上，记录膈神经和呼气性胸骨三角肌的活动以及延髓呼吸神经元的活动。在小脑下核刺激期间，呼气性延髓脊髓神经元和具有紧张性放电模式的神经元活动增加。在用 kainic 酸单侧损毁小脑下核后，胸骨三角肌放电消失，呼气性延髓脊髓神经元活动以降低的频率持续。刺激前间位核导致吸气和呼气活动均增加，而刺激蚓部后未出现系统性变化。结果表明，小脑下核受扰动后脊髓运动神经元呼气活动的至少一部分变化继发于延髓神经元活动的变化。讨论了小脑向延髓和脊髓神经元发出独立投射的可能性。
