Неуропхармацологи. 2012 Dec 7;67C:395-402. doi: 10.1016/j.neuropharm.2012.11.022.
Kawahara Y, Kaneko F, Иамада М, Kishikawa Y, Kawahara H, Ниши А.
извор
Department of Pharmacology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan. Electronic address: [емаил заштићен].
Апстрактан
Ghrelin is a stomach-derived orexigenic peptide. The goal of the study was to investigate the roles of mu and kappa opioid receptors in systemic ghrelin-mediated regulation of the mesolimbic допамин систем.
To evaluate the interaction of systemic ghrelin with values of храна reward, rats were exposed to храна removal, regular храна or palatable храна after systemic ghrelin administration. Extracellular допамин levels were quantified in the nucleus accumbens (NAc) and receptor-specific compounds were infused into the ventral tegmental area (VTA) using dual-probe microdialysis.
Consumption of regular or palatable храна without systemic ghrelin administration induced an increase in допамин levels in the NAc via activation of mu opioid receptors in the VTA. Systemic ghrelin administration (3 nmol, i.v.) followed by no храна induced a decrease in допамин levels via activation of kappa opioid receptors in the VTA. Systemic ghrelin administration followed by consumption of regular храна induced an increase in допамин levels via preferential activation of mu opioid receptors, whereas systemic ghrelin administration followed by consumption of palatable храна suppressed the increase in допамин levels via preferential activation of kappa opioid receptors.
Thus, natural храна reward and systemic ghrelin activate mu and kappa opioid receptor pathways in the VTA, respectively, resulting in opposite influences on допамин release in the NAc.
Furthermore, systemic ghrelin induces switching of the dominant opioid receptor pathway for highly rewarding храна from mu to kappa, resulting in suppression of the mesolimbic допамин систем. These novel findings might provide insights into the neural pathways involved in јело поремећаја.
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