TY - JOUR T1 - Electrical Inhibition of Identified Anorexigenic POMC Neurons by Orexin/Hypocretin JF - The Journal of Neuroscience JO - J. Neurosci. SP - 1529 LP - 1533 DO - 10.1523/JNEUROSCI.3583-06.2007 VL - 27 IS - 7 AU - Xiaosong Ma AU - Lejla Zubcevic AU - Jens C. BrĂ¼ning AU - Frances M. Ashcroft AU - Denis Burdakov Y1 - 2007/02/14 UR - http://www.jneurosci.org/content/27/7/1529.abstract N2 - Proopiomelanocortin (POMC) neurons of the hypothalamic arcuate nucleus (ARC) suppress appetite, and lack of POMC-derived peptides or electrical silencing of POMC neurons causes obesity. ARC POMC neurons are surrounded by nerve terminals containing the wakefulness-promoting peptides orexins/hypocretins, but whether orexin affects their electrical activity has not been tested directly. Here we identify living ARC POMC cells in mouse brain slices by targeted expression of green fluorescent protein. Using whole-cell patch-clamp recordings, we show that orexin suppresses the spontaneous action potential firing of these neurons. Orexin-induced inhibition involves membrane hyperpolarization, a decreased excitatory synaptic drive, and an increased frequency of GABAergic inputs. Our results suggest a reduction in the electrical activity of ARC POMC neurons, which is mediated by changes in presynaptic inputs, contributes to the appetite-enhancing action of orexins. ER -