针刺对动情周期不同阶段大鼠下丘脑性唤起刺激兴奋性神经元电活动的影响

目的:比较针刺不同穴位对动情周期不同阶段大鼠下丘脑性唤起刺激兴奋性神经元电活动的作用,为遴选针刺调节生殖内分泌功能的有效穴位、确定最佳治疗时机提供实验依据。方法:雌性SD大鼠,以阴道脱落细胞检测大鼠动情周期。动情前期/动情期大鼠14只,动情间期/动情后期大鼠18只。用玻璃微电极记录下丘脑内侧视前区、弓状核、室旁核部位神经元放电。刺激阴蒂模拟性唤起刺激,记录神经元放电反应,再从颈外静脉给大鼠注射β-雌二醇等,观察是否有反馈性作用,进一步鉴定所记录的神经元属性。以该神经元放电为指标,比较在动情周期不同阶段针刺不同穴位(8个)30 s对这类神经元的效应。实验在氨基甲酸乙酯(10%,1.0~1.2 g/kg)麻醉状态下进行。结果:从针刺的穴位看,动情前期/动情期雌鼠针刺后神经元放电增加的百分率由大到小的顺序为:"子宫"关元"足三里"肾俞"中脘"厥阴俞"内关"膻中";动情间期/动情后期:"关元"子宫"足三里"中脘"肾俞"厥阴俞"内关"膻中"。从针刺部位来看,下丘脑与阴蒂刺激相关的兴奋性神经元电活动增加的百分率由大到小的顺序为:下腹部(脐以下)、下肢、下背部(L1-S5)、上腹部(剑突-脐)、背部(T12以上)、胸部(剑突以上)、上肢。结论:针刺能有效调节下丘脑与模拟性唤起刺激相关的兴奋性神经元的电活动,但动情周期相同阶段针刺不同穴位和动情周期不同阶段针刺同一穴位对该神经元的激活效应不同,"子宫"关元"的激活效应较明显。针刺部位或穴位的神经节段支配与生殖器官的神经节段支配越接近,对下丘脑内性唤起刺激相关的神经元的激活作用越明显。

Effect of Acupuncture of Different Acupoints on Electrical Activities of Hypothalamic Sexual Arousal Stimulation-related Neurons at Different Stages of Oestrous Cycle in Rats

OBJECTIVE: To compare the effects of acupuncture stimulation of different acupoints on discharges of hypothalamic sexual arousal stimulation-related excitatory neurons in the rat so as to selected effective acupoints for regulating genito-endocrine function. METHODS: Experiments were performed in 32 female Sprague-Dawley rats. Examination of vaginal castoff cell smear (HE staining) was performed to determine the rats' estrous cycle. Those being in proestrus/estrus were 14 animals and those being in diestrus/metaestrus were 18. Extracellular discharges of neurons within the medial preoptic area, the arcuate nucleus and the paraventricular nucleus of the hypothalamus (AP: 4.0-9.0 mm, R: <1.0 mm, L: <2.0 mm) were recorded by using glass micro-pipettes in anesthetized rats (10% urethane). Sexual arousal stimulation was made by using a cotton-ball-stick to touch the clitoris repeatedly (30 s). When a marked change of the neuronal firing rate was found, beta-estradiol (20 ng/mL, 1.5-2.5 mL/kg) was injected intravenously from the external jugular vein for observing its feedback regulatory effect. Acupoints "Neiguan" (PC6), "Shanzhong" (CV17), "Jueyinshu" (BL14), "Zhongwan" (CV12), Shenshu" (BL23), "Guanyuan" (CV4), Z"igong" (EX-CA ) and "Zusanli" (ST 6) were punctured and stimulated manually by twirling the acupuncture needle continuously for 30 s. RRESULTS After manual acupuncture, the sequence of acupoints with a stronger excitatory reaction of the firing rates of the hypothalamic neurons related to sexual arousal stimulation was EX-CA1, CV4, ST36, BL23, CV12, BL14, PC6 and CV17 in proestrus/estrus; and CV4, EX-CA1, ST36, CV12, BL23, BL14, PC6 and CV17 respectively in diestrus/metaestrus. According to the place of the stimulated acupoints potentiating the electrical activity of the hypothalamic sexual arousal stimulation-related neurons, the sequence from stronger to the weaker responses was lower abdomen (below umbilicus), lower limb, lower back (L1-S5), upper abdomen, upper back (above T12), thorax, and upper limbs. After administration of estradiol, the excitatory response of these sexual arousal-related neurons decreased significantly in both estrus and non-estrus (P<0.05). CONCLUSION: Acupuncture can effectively activate the electrical activity of hypothalamic sexual arousal stimulation-related excitatory neurons. The closer the acupoint to the genital organs, the stronger is the excitatory effect, including "Zigong" (EX-CA1), "Guanyuan" (CV4) and "Zusanli" (ST36) among the 8 acupoints observed.