【摘要】 颈上交感神经与内脏神经的传出冲动表现同相变化,冲动群互相同步,冲动的幅度与频率变化和动脉血压的变化相呼应,但内脏神经对传入刺激的反应较之颈上交感神经更为明显。以单个电刺激作用于迷走或颈动脉窦神经向中端,可诱发交感传出冲动呈兴奋——抑制双相反应。如给予重复电刺激,交感冲动群发放的频率变成与刺激的频率同步,其最高频率可达每秒10—3次。更高频率时,不再表现规律性,转为连续的发放。停止刺激后,有后抑制现象。重复电刺激家兔减压神经或猫和兔的坐骨神经,能完全抑制交感神经干的冲动发放。同样,重复电刺激猫主动脉弓附近神经小枝时,引起交感干持续、强烈的冲动发放。如同时刺激猫的主动脉弓处神经小枝及坐骨神经,则在一定的刺激频率下,交感冲动亦与刺激同步,最高可达7—8次/秒。以重复电刺激直接作用于延髓加压区,可得到良好的交感传出冲动节律同步的反应。刺激闩都附近可完全抑制交感传出冲动,但长期刺激下,能在抑制下释放出来,表现与刺激节律同步的冲动发放,以上两种同步的最高频率亦可达10—13次/秒。在延髓以上水平切断脑干,不影响上述机能;在闩部前方切断脑干,交感冲动大部分消失,也不能再产生反射性变化。以上结果说明,在刺激迷走和窦神经时所引起的交感传出冲动群的节律性,乃由于此两种传入神经中含有抑制性和兴奋性两种纤维。在其影响下,中枢交替发生兴奋与抑制,从而反映于传出冲动。更多还原

【Abstract】 The post-ganglionic discharges from the cervical sympathetic and the splanchnic nerves were recorded in 68 rabbits and 3 cats anaesthized with urethane or urethane and chloralose. Arterial blood pressure was also recorded in some experiments. The patterns of efferent discharge were similar among the various sympathetic nerves. A rise of blood pressure followed an increase of frequency of discharges of the sympathetic, and a fall followed a decrease, with a lag of about 1-3 seconds. A single stimulus applied to the central stump of the cervical or abdominal vagus or of the carotid sinus nerve induced, after a short latency, a phase of augmentation of discharges lasting for 0.07-0.15 second, and then followed by a diminution of discharge. But the stimulation of the sciatic nerve and of the depressor nerve of the rabbit usually only induced an inhibition of the efferent sympathetic discharge. When the afferent fibres of peripheral nerves were stimulated with low frequency repetitive shocks, grouping of the efferent sympathetic discharges synchronous with the rhythm of the stimulus could be observed. In the rabbit, during vagus and sinus nerve stimulation the highest frequency was 10 to 13 per second, but when the somatio and the depressor nerves were stimulated, the highest frequency was only 3 to 5 per second. Repetitive stimulation of the aortic nerve of the cat only induced continuous sympathetic activity, but when the aortic nerve and the sciatic nerve were stimulated simultaneously, synchronization of the efferent bursts with the rhythm of the stimuli could be obtained. Low frequency stimulation of the pressor area in the medulla also induced bursts of the sympathetic discharge synchronized with the frequency of stimulation. Efferent sympathetic discharges were first inhibited by stimulating the depressor area at the obex, but discharges synchronous with stimulus gradually appeared later in spite of the stimulation.更多还原