电针“内关”穴抑制刺激兔下丘脑诱发的室性心律失常作用机制研究

目的:研究下丘脑弓状核区及其中阿片肽受体是否参与电针"内关"穴抑制刺激兔下丘脑诱发的室性心律失常(HVA)作用。方法:(1)损毁弓状核区对电针"内关"穴抑制室性期前收缩(HVE)的影响。健康家兔4只,乌拉坦麻醉,人工呼吸,注射三碘季胺酚制动。恢复2 h后,恒流电刺激下丘脑中线区(50 Hz,波宽0.5 ms,刺激电流强度为0.4~0.8 mA,刺激时间为5~10 s,每5 min 1次),出现数目较稳定的HVE后,行"内关"电针3 min,共4次。电损毁弓状核区,20 min后,再观察电针"内关"穴的效果。(2)弓状核微量注射吗啡对HVE的影响。家兔12只,吗啡和生理盐水组各6只。当引起稳定的HVE后,向弓状核区注射吗啡(2μg/μl),再观察HVE的改变。(3)弓状核区微量注射纳络酮对电针"内关"穴抑制HVE效应的影响。家兔12只,纳络酮和生理盐水组各6只,在同一只动物上依序进行:①弓状核区微量注射纳络酮前电针"内关"穴抑制HVE效应观察;②弓状核区微量注射纳络酮或生理盐水对HVE的影响;③弓状核区微量注射纳络酮(2μg/μl)对电针"内关"穴抑制HVE效应的影响。结果:电针兔"内关"穴可以显著抑制HVE;损毁弓状核区后,电针"内关"穴抑制HVE的效应消失;在弓状核区微量注射吗啡能抑制HVE的发生;而在弓状核区微量注射纳络酮后,电针"内关"穴抑制HVE的效应出现反转。结论:电针"内关"穴抑制HVE的效应与弓状核内阿片受体有关。

Study on the Mechanism of Electroacupuncture of "Neiguan"(PC 6)in Inhibiting Ventricular Arrhythmia Induced by Hypothalamic Electrostimulation in the Rabbit

Objective To research whether opiate receptors in the hypothalamic arcuate nuclei (ARC) participate in the inhibitory effect of electroacupuncture (EA) of "Neiguan" (PC 6) on ventricular arrhythmia in the rabbit. Methods This research consists of three parts. 1) Effect of electrolytic lesion of hypothalamic ARC on EA-induced suppression of heart ventricular extrasystole(HVE): HVE model was established by electric stimulation (0. 4 - 0. 8 mA, wave-duration 0. 5 ms, 50 Hz, 5- 10 s every 5 min) of hypothalamic midline region (R/L: 0. 5- 1. 5 mm; H: -5-4. 5 mm) in 4 rabbits. Electrolytic lesion (5 mA, 20 s) was induced by delivering a direct current to ARC region (A 1, L/R: 0. 5 mm, H: -7 mm) through a stainless steel electrode (anode). EA (0. 25 mA,5 Hz, pulse-duration 0. 5 ms) was applied to "Neiguan" (PC 6) for 3 min, 4 times altogether. (2) Effect of microinjection of morphine in ARC area on HVE: After inducing HVE, morphine (2 μg/ul) was injected into hypothalamic ARC region, and changes of HVE number were observed in 12 rabbits (6 for morphine group and the other 6 for normal saline group). (3) Effect of ARC microinjection of naloxone on EA-induced suppression of HVE: After inducing stable HVE, microinjection of naloxone (2 μg/μl)or same dose of normal saline was performed into ARC region in 6 rabbits respectively, followed by EA of PC6. Results Electric stimulation of hypothalamic midline region could induce continuous HVE. After EA, it decreased significantly in the occurrence rate (P<0. 01). Following ARC region lesion, the effect of EA in inhibiting HVE disappeared. After microinjection of morphine into ARC region, the occurrence rate of HVE reduced apparently (P<0. 01), while after microinjection of naloxone, the inhibitory effect of EA vanished. No significant changes were found in the occurrence rate and the inhibitory rate of HVE after microinjection of naloxone or normal saline in the ARC region (P>0. 05). Conclusion Hypothalamic ARC and it's opium receptors participate in the inhibitory effect of EA on hypothalamic midline region electro-stimulation-induced HVE in the rabbit.