刺激犬体表感受器兴奋心脏表面神经元对心脏功能的影响

为了观察体表刺激对犬心脏表面神经元活动及对心脏功能的影响,定量敲击麻醉开胸犬的左胸壁、上腹壁,同步记录犬右心房神经节丛神经元内单位放电的频数及心脏变时、变力性反应。结果：敲击左胸壁、上腹壁均可使右心房神经节丛内神经元在１０ｓ内单位放电频数增加,同时伴有心率减慢和室心律失常。静脉注射普萘洛尔（１ｍｇ／ｋｇ）,可使刺激体表引起的室性心律失常反应减少。静脉注射阿托品（１ｍｇ／ｋｇ）使刺激体表引起的心率减慢反应未完全消除;心脏急性去神经支配后,敲击体表对引起神经元的放电频数和变时反应均无明显影响。本研究说明：敲击犬心前区和上腹壁可直接引起心脏表面神经节丛内的副交感神经元兴奋,窦房结自律性降低,引起负性频率作用;在此基础上刺激兴奋了心脏表面交感神经元可诱发室性心律失常。由于传入通路被切断影响上述反应,提示：接受刺激的体表感受器或神经纤维与心脏表面神经元之间存在着一定的联系。

BRADYCARDIA AND VENTRICULAR ARRHYTHMIA INDUCED BY ACTIVATING CANINE INTRINSIC CARDIAC NEURONS THROUGH KNOCKING AT CHEST AND ABDOMINAL WALL

In order to observe the effects ofstimulating bodysurface on cardiac neuronal activities and cardial functions canine intrinsic cardiacneuronal spontaneous activities and inotropic andchronotropic responses wete recorded while koncking (3kg) at chest and abdominal wall of anesthetized open-chest dogs. Activity increasing of theunits in right atrial ganglionated plexus was alwaysassociated with bradycardia or/and ventricular arrhythmia after knocking at the precordial and abdominal region. Inotropic responses were not elicited following the interference. After intravenous administration of propranolo(1mg/kg iv), ventriculararrhythmia was reduced;and then atropine (1 mg/kg iv), bradycardia was not eliminated completely.Following acute decentralization, the changes ofneuronal spontaneous activity and chrontropic responses could still be induced simultaneously. Suggestion: knocking at precordial and abdominal region could stimulate parasympathetic neurons inright atrial ganglionated plexus, and then inducedbradycardia, and stimulate sympathetic neurons,which could induce ventricular arrhythmia. Becauseacute decentralization affects those reactions, thereis some relationship between nerve fibers or bodysurface receptors and cardiac neurons.