肌梭传入对呼吸的调节作用

Effects of muscle spindle afferents on the regulation of respiration in rabbit

实验用 6 3只麻醉、制动、切断双侧颈迷走神经、人工呼吸的家兔 ,以延髓呼吸相关神经元 (RRN)和膈神经放电 (Phr D)作为呼吸观测指标 ,观察了股动脉注射琥珀胆碱 (Sch)诱发的肌梭传入活动对呼吸的影响。结果显示 :(1)股动脉注射Sch可产生明显的呼吸易化作用 ,主要表现为吸气时程 (Ti)延长 ,呼气时程 (Te)缩短不明显 ,Ti/Te比值增加以及呼吸频率 (RF)变化不大 ,称为吸气延长效应 ;或Te缩短 ,Ti变化不明显 ,Ti/Te比值增加 ,RF加快 ,称为抑呼增频效应。 (2 )股动脉注射Sch对延髓吸气神经元的作用以兴奋为主 (37/ 5 6 ) ,对呼气神经元的作用以抑制为主 (10 / 17) ,而对非呼吸性神经元这种兴奋与抑制反应均不明显。 (3)Sch对吸气神经元的兴奋作用 ,一般在给药后 1～ 2min即可达高峰 ,而对呼气神经元的抑制作用则发生较晚 ,一般在给药后 2～ 3min达高峰。(4 )肌注布比卡因破坏肌梭后 ,可明显降低Sch对延髓呼吸相关神经元和膈神经放电的影响。结果提示 ,肌梭的传入活动可通过延髓或延髓上中枢的下行作用参与对呼吸节律的反射性调节作用。

Effect of muscle spindle afferent invoked by intraarterial injection of succinylcholine (Sch) on respiration was assessed by changes in unit discharge of respiration related neurons and phrenic nerve of 63 anesthetized, bilaterally vagotomized and artificially ventilated rabbits. The results are as follows. (1) Intra^arterial injection of Sch prolonged inspiratory duration (Ti) or decreased expiratory duration (Te) and augmented respiratory frequency (RF). (2) 66% (37/56) of the medullary inspiratory neurons were excited and 10/17 of the expiratory neurons were inhibited by intraarterial injection of Sch, reaching maximum respectively at 1～2 and 2～3 min after injection, while non respiration related neurons were not affected. (3) This effect of Sch was suppressed or abolished when muscle spindles were destroyed by intramuscular injection of bupivacaine.[WT5HZ]