title: Assessment of a small molecule melanocortin-4 receptor-specific agonist on energy homeostasis.
abstract: The central melanocortin system has been demonstrated to play an important role in regulating different aspects of energy homeostasis. Understanding the specific contributions of MC3 and MC4 receptors, however, requires specific agonists and antagonists for each of the predominant forms of brain melanocortin receptors, MC3-R and MC4-R. We report here the characterization of a small peptide mimetic MC4-R-specific agonist that possesses both high affinity (K(i)=11.3 nM) and potency (EC(50)=1.62 nM) in vitro and is capable of inhibiting feeding behavior in mice when administered intracerebroventricularly (i.c.v.). Depending on the paradigm, acute (1 h following an overnight fast) or long-term (greater than 6 h under normal nocturnal feeding conditions) feeding inhibition was observed following icv injection. No effect on long-term feeding inhibition was observed with this compound in MC4-R knockout mice, and central administration of this compound had no effect on either metabolic rate or insulin release.
authors.affiliation: Vollum Institute, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Mail Code: L474, Portland, OR 97201, USA.
authors.forename: David
authors.initials: D
authors.lastname: Cepoi
authors.forename: Teresa
authors.initials: T
authors.lastname: Phillips
authors.forename: Mary
authors.initials: M
authors.lastname: Cismowski
authors.forename: Val S
authors.initials: VS
authors.lastname: Goodfellow
authors.forename: Nick
authors.initials: N
authors.lastname: Ling
authors.forename: Roger D
authors.initials: RD
authors.lastname: Cone
authors.forename: Wei
authors.initials: W
authors.lastname: Fan
mesh_terms: D000818:Animals; D002460:Cell Line; D004435:Eating / Q000187:drug effects / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D044105:Receptor, Melanocortin, Type 4 / Q000819:agonists* / Q000172:deficiency / Q000502:physiology; D044005:Tetrahydroisoquinolines / Q000138:chemical synthesis / Q000494:pharmacology*; D014230:Triazoles / Q000138:chemical synthesis / Q000494:pharmacology*
chemical_list: C467221:N-(1,2,3,4-tetrahydroisoquinolinium-3-ylcarbonyl)-1-(4-chlorobenzyl)-2-(4-cyclohexyl-4-(1H-1,2,4-triazol-1-ylmethyl)piperidin-1-yl)-2-oxoethylamine; D044105:Receptor, Melanocortin, Type 4; D044005:Tetrahydroisoquinolines; D014230:Triazoles