title: Ghrelin receptor antagonism attenuates nicotine-induced locomotor stimulation, accumbal dopamine release and conditioned place preference in mice.
abstract: BACKGROUND
  The orexigenic peptide ghrelin activates the reward systems, specifically the cholinergic-dopaminergic reward link, suggesting that ghrelin may increase the incentive salience of motivated behaviours such as food seeking. Moreover, central ghrelin signalling, involving the growth hormone secretagogue receptor 1A (GHS-R1A), is required for the rewarding properties, as measured by locomotor stimulation, accumbal dopamine release and conditioned place preference, of alcohol, cocaine as well as amphetamine. As the target circuits for other drugs of abuse, including nicotine, in the brain includes this reward link, we sought to determine whether the central ghrelin signalling system is involved in nicotine's activation of this system.
  
  
  METHODS
  This was investigated by studying the effects of peripheral administration of a GHS-R1A antagonist (JMV2959) on the nicotine-induced locomotor simulation, accumbal dopamine release and conditioned place preference.
  
  
  RESULTS
  In the present study we found that the ability of nicotine to increase the locomotor activity, accumbal dopamine release and to condition place preference were reduced in mice treated with a GHS-R1A antagonist.
  
  
  CONCLUSIONS
  Thus GHS-R1A appears to be required not only for alcohol, cocaine and amphetamine-induced reward, but also for reward induced by nicotine. Our data suggest that the central ghrelin signalling system may constitute a novel potential target for treatment of drug dependence.
authors.affiliation: Section for Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, SE-405 30 Gothenburg, Sweden. elisabet.jerlhag@pharm.gu.se
authors.forename: Elisabet
authors.initials: E
authors.lastname: Jerlhag
authors.forename: Jörgen A
authors.initials: JA
authors.lastname: Engel
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects*; D004298:Dopamine / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D051379:Mice; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects; D054440:Receptors, Ghrelin / Q000037:antagonists & inhibitors* / Q000502:physiology; D014230:Triazoles / Q000494:pharmacology*
chemical_list: C569751:N-(1-(4-(4-methoxybenzyl)-5-phenethyl-4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-aminoacetamide; D018722:Nicotinic Agonists; D054440:Receptors, Ghrelin; D014230:Triazoles; D009538:Nicotine; D005998:Glycine; D004298:Dopamine