Neuromedin U neurones in the rat nucleus of the tractus solitarius are catecholaminergic and respond to peripheral cholecystokinin.

Centrally administered neuromedin U (NMU) has profound effects on food intake and energy expenditure. In the rat, central expression of NMU mRNA is confined to the brainstem and the hypothalamus/pituitary, while mRNA for the receptor NMU2R is expressed in the hypothalamus and hippocampus, as well as in the lining of the ventricular system, but not in the brainstem. We demonstrate that a subpopulation of catecholaminergic neurones in the brainstem nucleus of the tractus solitarius contain NMU and are activated by the gut-derived peptide, cholecystokinin. This is consistent with NMU neurones having an anorectic action, probably via their interaction with other neurones in the paraventricular hypothalamus.