【摘要】 背景:迄今为止呼吸节律的准确起源位置和其形成机制仍不清楚。作者以前的实验发现轻触压延髓腹侧表面舌下神经根部,家兔呼吸会立即停止。目的:观察在整体情况下,机械损毁家兔面神经后核内侧区对呼吸节律的影响。设计:随机对照实验。单位:昆明医学院生理教研室。材料:实验于2002-02/12在昆明医学院生理教研室进行。动物为实验用健康家兔54只,其中22只从延髓背侧面定位并机械损毁双侧面神经后核内侧区,18只从延髓腹侧面定位损毁,14只用于观察机械损毁面神经后核内侧区后血压和心率的变化。方法:分别暴露家兔延髓腹面侧和背面侧,切断双侧迷走神经,记录一侧膈神经放电作为呼吸指标,应用直径为0.8mm或0.4mm的不锈钢管损毁面神经后核内侧区,观察机械损毁对呼吸的影响。另取家兔14只,机械损毁双侧面神经后核内侧区,在机械损毁后1～3min家兔血压和心率的变化。主要观察指标:①机械损毁双侧面神经后核内侧区致呼吸节律改变。②膈神经放电数及呼吸频率。③②损毁后1～3min内血压和心率的变化。结果:54只家兔均进入结果分析。①从延髓腹侧面机械损毁双侧面神经后核内侧区致呼吸节律不可逆消失的总阳性率为67%(12/18),而从延髓背侧面机械损毁的总阳性率仅为14%(3/14)。②出现呼吸节律不可逆消失的所有家兔的膈神经节律性放电明显稀少,不规则。膈神经放电的吸气时程和呼气时程显著延长,当呼气时程极度延长时,呼吸节律消失,动物呼吸停止于呼气相。②部分机械损毁双侧面神经后核内侧区时,家兔(n=27)的呼吸仍存在,但立即表现出明显的呼吸抑制,呼吸频率显著变慢[(43.5±6.4)%,P<0.001],膈神经放电数显著减少[(42.0±3.7)%,P<0.001],膈神经放电的吸气时程和呼气时程均显著延长,但以呼气时程的延长极为显著。④对上述各损毁点做组织学检查,引起呼吸停止或呼吸明显减弱的位点均在面神经后核内侧区内。⑤在损毁后1～3min内,兔的心率和血压略有波动,变化幅度5%～7%,和正常值相比差异无显著性(P>0.05)。结论:面神经后核内侧区可能是呼吸节律产生的主要部位,而面神经后核内侧区中的呼吸相关神经元则可能是形成呼吸节律的重要组成部分。更多还原

【Abstract】 BACKGROUND:Until now,the definite source of respiratory rhythm generation and the ontogenic mechanism are still in controversy.Previous our investigating indicated that respiration would stop due to the gentle press on the hypoglossal root under the surface of ventral medulla of rabbit.OBJECTIVE:To observe the influence of mechanical lesion in medial region of nucleus retrofacialis on respiratory rhythm of a living rabbit model.DESIGN:Randomized controlled study. SETTING:At the Physiology Teaching Room of Kunming Medical College. MATERIALS:This study was carried out at the Physiology Teaching Room of Kunming Medical College from February 2002 to December 2002. Totally 54 healthy rabbits were randomly selected,amongst which 22 rabbits were submitted to the mechanical damage of the medial region of bilateral nucleus retrofacialis by the dorsal processes,and 18 received the same damage by the ventral process,14 rabbits used for observing the changes of blood pressure and heart rate due to the mechanical damage.METHODS:The ventral and dorsal medullar of rabbits were exposed and the bilateral vagotomy at the cervical level were cut. Discharge of the phrenic nerve was used as the respiratory index.Stainless pipe of 0.8 mm or 0.4 mm diameter was used to make mechanical damage at the medial region in order to investigate the changes of respiration.Fourteen rabbits were selected and submitted to the bilateral mechanical damage, the changes of blood pressure and heart rate were observed at posttraumatic 1-3 minutes.MAIN OUTCOME MEASURES:①The changes of respiratory rhythm induced by the mechanical damage of the medial region of bilateral nucleus retrofacialis.②The number of phrenic nerve discharge and respiratory frequency.③The changes of blood pressure and heart rate at postlesion 1-3 minutes.RESULTS:Data of 54 rabbits were analyzed.①Irreversible disappearance of respiratory rhythm was found in 12 out of 18 rabbits (the positive rate was 67%) due to the mechanical damage by the ventral processes, comparing to 3/14 (14%) by the dorsal process.②Rhythmic discharge of phrenic nerve became scarce and irregular in all rabbits who has irreversible disappearance of respiratory rhythm, the inspiratory and expiratory discharging phase were significantly prolonged,moreover respiratory rhythm would disappear if expiratory phase was extremely extended, respiration stopped at expiratory phase.③When the medial region of bilateral nucleus retrofacialis was partially destroyed,the still existed respiration of 27 rabbits was found immediately inhibited, phrenic nerve discharge frequency obviously decreased[(43.5±6.4)%,P< 0.001],and its discharge number was significantly decreased[(42.0±3.7)%,P< 0.001], moreover the inspiratory and expiratory discharging phase were found obviously extended,with expiratory phase was in particular.④From the results of histological examination on the above mechanical lesion.Respiration stop or obvious attenuation was found mostly due to the damage at the medial region of nucleus retrofacialis.⑤The blood pressure and heart rate changed slightly by 5%-7%at posttraumatic 1-3 minutes,there was not significantly different from the normal value(P >0.05). CONCLUSION:The medial region of nucleus retrofacialis might be the main source of respiratory rhythm generation,and the related neuron within it would be the important component involving in the generation of respiratory rhythm.更多还原