Ghrelin has been attributed various physiological processes including food intake and reward regulation, through activation of the mesolimbic dopamine system. Reward modulation involves the mesolimbic dopamine system, consisting of the ventral tegmental area (VTA) dopamine neurons targeting nucleus accumbens (NAc), a system that ghrelin activates through VTA-dependent mechanisms. In the first study, we found that systemic intraperitoneal (ip) administration of rimonabant attenuated intracerebroventricular (icv) ghrelins ability to cause locomotor stimulation and NAc dopamine release in mice. Ghrelin-induced (icv) chow intake was not altered by rimonabant administration (ip). Finally, we showed that bilateral VTA administration of rimonabant blocks the ability of intra-VTA administered ghrelin to increase locomotor activity, but does not affect food intake in mice. Collectively, these data indicate clear dissociation between regulation of food intake and activation of the mesolimbic dopamine system.
Funding Agencies|Swedish Research Council [2015-03219]; Swedish Society for Medical Research; Swedish Brain Foundation; LUA/ALF from the Sahlgrenska University Hospital [148251]; Torsten Soderberg; Alcohol research council of the Swedish alcohol retailing monopoly; foundation of Adlerbertska; foundation of Fredrik and Ingrid Thuring; foundation of Tore Nilsson; foundation of Langmanska; foundation of Wilhelm and Martina Lundgren; foundation of Knut and Alice Wallenberg; foundation of Magnus Bergvall; foundation of Aners; foundation of Jeansons; foundation of Ake Wiberg; foundation of NovoNordisk; Swedish Society of Medicine