Neuropeptide Y-mediated inhibition of proopiomelanocortin neurons in the arcuate nucleus shows enhanced desensitization in ob/ob mice.
NPY and alphaMSH are expressed in distinct neurons in the arcuate nucleus of the hypothalamus, where alphaMSH decreases and NPY increases food intake and body weight. Here we use patch-clamp electrophysiology from GFP-labeled POMC and NPY neurons to demonstrate that NPY strongly hyperpolarized POMC neurons through the Y1R-mediated activation of GIRK channels, while the alphaMSH analog, MTII, had no effect on activity of NPY neurons. While initially NPY had similar effects on POMC neurons derived from ob/ob mice, further studies revealed a significant increase in desensitization of the NPY-induced currents in POMC neurons from ob/ob mice. This increase in desensitization was specific to NPY, as GABA(B) and microOR agonists showed unaltered desensitization in POMC neurons from ob/ob mice. These data reveal an intricate and asymmetric interplay between NPY and POMC neurons in the hypothalamus and have important implications for the delineation of the neural circuits that regulate feeding behavior.
Laboratory of Molecular Genetics, The Rockefeller University, 1230 York Avenue, Box 305, New York, NY 10021, USA.
Aaron G
AG
Roseberry
Hongyan
H
Liu
Alexander C
AC
Jackson
Xiaoli
X
Cai
Jeffrey M
JM
Friedman
D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects / Q000502:physiology*; D001418:Baclofen / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D066298:In Vitro Techniques; D051379:Mice; D008820:Mice, Obese; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009478:Neuropeptide Y / Q000502:physiology*; D011333:Pro-Opiomelanocortin / Q000037:antagonists & inhibitors* / Q000502:physiology
D009478:Neuropeptide Y; D004744:Enkephalin, Methionine; D011333:Pro-Opiomelanocortin; D001418:Baclofen