Nesfatin-1, corticotropin-releasing hormone, thyrotropin-releasing hormone, and neuronal histamine interact in the hypothalamus to regulate feeding behavior

Nesfatin-1, corticotropin-releasing hormone (CRH), thyrotropin-releasing hormone (TRH), and hypothalamic neuronal histamine act as anorexigenics in the hypothalamus. We examined interactions among nesfatin-1, CRH, TRH, and histamine in the regulation of feeding behavior in rodents. We investigated whether the anorectic effect of nesfatin-1, a-fluoromethyl histidine (FMH; a specific suicide inhibitor of histidine decarboxylase that depletes hypothalamic neuronal histamine), a CRH antagonist, or anti-TRH antibody affects the anorectic effect of nesfatin-1, whether nesfatin-1 increases CRH and TRH contents and histamine turnover in the hypothalamus, and whether histamine increases nesfatin-1 content in the hypothalamus. We also investigated whether nesfatin-1 decreases food intake in mice with targeted disruption of the histamine H1 receptor (H1KO mice) and if the H1 receptor (H1-R) co-localizes in nesfatin-1 neurons. Nesfatin-1-suppressed feeding was partially attenuated in rats administered with FMH, a CRH antagonist, or anti-TRH antibody, and in H1KO mice. Nesfatin-1 increased CRH and TRH levels and histamine turnover, whereas histamine increased nesfatin-1 in the hypothalamus. Immunohistochemical analysis revealed H1-R expression on nesfatin-1 neurons in the paraventricular nucleus of the hypothalamus. These results indicate that CRH, TRH, and hypothalamic neuronal histamine mediate the suppressive effects of nesfatin-1 on feeding behavior.