Effects of Electroacupuncture on Electrical Activity of Neurons of Hypothalamic Perifornical Nucleus and on Hypothalamic and Plasma Leptin and Insulin Levels in Obesity Rats

Objective:To explore the effect of electroacupuncture (EA) on the nervous function of hypothalamic perifornical nucleus (PeF) in obesity rats.Methods: Thirty-six SD male rats were randomly and evenly divided into normal control group, model group and acupuncture group. Changes of body weight, Lee’s index, body fat, hypothalamic and serum leptin (LP) and insulin (INS) contents as well as spontaneous discharges of neurons in hypothalamic PeF were observed in obesity rats. EA (10 Hz, 1.5 V and continuous waves) was applied to “Zusanli”(ST 36) and “Neiting”(ST 44) for 10 min, once daily and continuously for 14 days. Hypothalamic tissue and serum LP and INS contents were assayed with radioimmunoassay. Electrical activity of PeF neurons were recorded by using micro-electrodes. Results: The body weight, Lee’s index, body fat, the levels of serum LP and INS as well as the discharge rate of PeF neurons in obesity rats were all markedly higher than those in normal rats, while the levels of hypothalamic LP and INS in obesity rats were strikingly lower than those in normal rats (P<0.05～0.01). Compared with model group, the body weight, Lee’s index, body fat, serum LP and INS as well as the discharge rate in acupuncture group all lowered significantly (P< 0.05～0.01); while hypothalamic LP and INS increased remarkably (P<0.01). There were positive interrelations between the spontaneous discharge rate of PeF neurons and the obesity index, between the discharge rate and the serum LP and INS levels (P<0.05～0.01). There were negative interrelations between the spontaneous discharge rate of PeF neurons and the levels of hypothalamic LP and INS. It indicated that acupuncture treatment could induce weight loss, lower serum LP and INS as well as the spontaneous discharges of PeF neurons, and raise hypothalamic LP and INS contents markedly. Conclusion: Acupuncture treatment induced decrease of peripheral LP and INS levels and reduction of the activity of PeF neurons and increase of central LP and INS contents may be responsible for the effect of acupuncture in antiobesity.