Mapping CNS Response to Leptin by MEMRI

A-B-M-A Asad¹, Serene Y. L. Tong¹, Ma Wei², Weiping Han², Kai-Hsiang Chuang¹

Leptin signaling in CNS plays an important role in regulating energy homeostasis which inhibits food intake and increases energy expenditure. To understand the CNS response to leptin, we used manganese enhanced MRI to observe dynamic changes in hypothalamic nuclei by Mn2+ as an Ca2+ activity dependent agent during fasting and peripheral leptin injection. We observed signal changes in arcuate, paraventricular, ventromedial and dorsomedial nuclei in hypothalamus. Injection of leptin suppressed signal significantly in most nuclei in fasted animals. In non-fasted animals, however, leptin injection increased signal in most nuclei but not arcuate. This method can be applied to study hypothalamic function in response to different metabolic signals and hypothalamic dysfunction in animal models of leptin resistance.