Arcuate nucleus of hypothalamus is involved in mediating the satiety effect of electroacupuncture in obese rats

Obesity is a major health problem in the world. Since effective remedies are rare, researchers are trying to discover new therapies for obesity, and acupuncture is among the most popular alternative approaches. This study investigated the anti-obesity mechanisms of EA, using a rat model of diet-induced obesity. After feeding with a high-fat diet for 9 weeks, a number of rats who gained weight that surpassed the maximal body weight of rats in the chow-fed group were considered obese and employed in the study. A 2 Hz EA treatment at the acupoints ST36/SP6 with the intensity increasing stepwise from 0.5-1-1.5 mA was given once a day for 30 min. Rats treated with EA showed significantly decreased food intake and reduced body weight compared with the rats in DIO and restraint group. EA treatment increased peptide levels of alpha-MSH and mRNA levels of its precursor POMC in the arcuate nuclear of hypothalamus (ARH) neurons. In addition, the cerebral spinal fluid (CSF) content of alpha-MSH was elevated by EA application. ARH lesions by monosodium glutamate abolished the inhibition effect of EA on food intake and body weight. A non-acupoint stimulation did not show the benefit effect on food intake inhibition and body weight reduction compared with restraint and ST36/SP6 EA treatment. We concluded that EA treatment at ST36/SP6 acted through ARH to significantly inhibit food intake and body weight gain when fed a high-fat diet and that the stimulation of alpha-MSH expression and release might be involved in the mechanism. (C) 2011 Elsevier Inc. All rights reserved.