Hypothalamic microdialysis of mazindol causes anorexia with increase in synaptic serotonin in rats

Brain microdialysis was used to determine if lateral hypothalamic serotonin (5-HT) is involved in the mazindol-induced anorexia in rats. Direct application of mazindol through a microdialysis membrane both significantly increased the 5-HT levels in the lateral hypothalamus and suppressed food intake by fasted rats. The increase in 5-HT concentration was dose related and the concentration of mazindol for half-maximal response was 4.6 μM. Pretreatment with methysergide, a potent 5-HT receptor-blocking agent, significantly antagonized the mazindol-induced anorexia. These results suggest that the anorectic action of mazindol might be mediated, at least in part, through serotonergic mechanisms in the hypothalamus.