[Effects of electro-acupuncture on signal transduction pathway of hypothalamic neuroendocrine system in ovariectomized rats].

Objective: To compare the varieties and contents of the main nerval information molecules in perfusate from hypothalamic medial preoptic area (MPOA) of the rats in different sexual cycles and the ovariectomized rats treated by electro-acupuncture, so as to observe the similarities and differences of hypothalamic neuroendocrine signal transduction pathway under the physiological and pathological status, and to explore the mechanisms of neuroendocrine signal transduction of electro-acupuncture therapeutic effect in perimenopausal syndrome.

Methods: The stereo localization technique and push-and-pull perfusion of the rat brain nucleus were adopted for collecting the hypothalamic MPOA perfusate of the female rats with normal sexual cycle, and also for collecting the MPOA perfusate of ovariectomized rats after electro-acupuncture treatment as acupuncture perfusate (AP). After being respectively microinjected into MPOA of the ovariectomized rats, the influence of the different perfusates on vagina cytology and serum estradiol (E2) level was observed. The contents of gonadotropin-releasing hormone (GnRH), dopamine (DA), gamma-aminobutyric acid (GABA), glutamate (Glu), aspartate (Asp) and beta-endorphin (beta-EP) in the perfusate of each group were detected by radioimmunoassay or high performance liquid chromatography, and then the varieties and contents of these substances in the perfusate of each group were compared and analyzed.

Results: The contents of neural active substances including DA, GABA, Glu, and beta-EP in the perfusate from the rats' MPOA during different stages of sexual cycle showed some regular changes. After the perfusate was microinjected respectively into the MPOA of the ovariectomized rats, the changes of animal vaginal exfoliated cells and serum E2 level showed the similar four-stage cycle characteristics as normal rats; the changes of vaginal exfoliated cells and serum E2 level of the ovariectomized rats without electro-acupuncture treatment showed the acupuncture-like effects following the microinjection of AP in the MPOA.

Conclusion: The information molecules in the perfusate from MPOA of rats in normal sexual cycle or electro-acupuncture-treated rats include classical neurotransmitters, amino acid neurotransmitters, and neuropeptides. Acupuncture may modulate the release and synthesis of these information molecules to normalize the subnormal function of MPOA in perimenopausal period. Thus, AP may be a neuroendocrine signal carrier of acupuncture effects for acupuncture signal transduction from one individual to another. This may provide a new thinking and method for studying acupuncture signal transduction of the acupuncture therapeutic effects on perimenopausal syndrome.