【摘要】 (一)在不同的麻醉型式下,对28只犬进行79次静脉内输入生理盐水或自体的肝素化血液,结果引起心率减慢的占62%、加速的占28%和变化不明显的占10%。(二)在颈部切断两侧迷走神经或同时切断迷走神经和切除星状神经节后,70次输液中引起心率减慢的占44%、加速的占14%和变化不明显的占42%,说明输液对心率的影响只有部分是通过神经反射机制的。(三)在输液引起的静脉压增高与心率变化之间无恒定的相关;暂时开放一侧颈总动脉与上腔静脉之间的动静脉瘘而致静脉回流增多时,虽不伴有静脉压的明显波动,但在半数实验中得以诱发心率加速。(四)输液所致心率变化的方向,与动物的原初心率有关;原初心率较高的(200次/分左右),输液常引起心率减慢,原初心率低的(低于100次/分),输液则大半引起心率加速。这种关系在切除心脏的神经后不变。2只利血平处理犬原初心率在100次/分左右,但输液后心率变化不显著。(五)根据上述实验结果,可以认为,所谓的 Bainbridge 反射不是一个恒定的生理机制。更多还原

【Abstract】 (1)Under various anaesthetics,28 dogs were given a total of 79 infusions of normal saline or heparinized blood,out of which 49 evoked bradycardia (62%),22 tachycardia(28%)and 8 no significant chronotropic effect(10%). (2)Of 70 infusions made after the cervical vagotomy with or without stellate ganglionectomy,31 showed bradycardia(44%),10 tachycardia(14%)and 29 no significant chronotropic effect(42%).It was therefore suggested that the chronotropic response could only partly be accounted for by reflex mechanisms involving the extrinsic nerves. (3)There was no constant correlation between the increase in venous pressure due to infusion and the chronotropic response;the temporary opening of arterio- venous fistula,which apparently augmented the venous return,brought about cardiac acceleration in spite of the fact that there was no marked increase in venous pressure. (4)The direction of chronotropic response depended to some extent upon the initial heart rate of the animal,since in dogs with high initial heart rate(about 200/ min),infusions always evoked bradycardia,while those with relatively low heart rate (100/rain)infusions induced tachycardia in most cases.In 2 reserpinized dogs with low initial heart rate(about 100/min),infusions elicited no apparent response. (5)From the experiments above,the so-called Bainbridge reflex seemed not to be a constant physiological mechanism for the regulation of heart rate in response to infusion.更多还原