Ghrelin increases anxiety-like behavior and memory retention in rats.
Ghrelin is a peptide found in the hypothalamus and stomach that stimulates food intake and whose circulating concentrations are affected by nutritional state. Very little is known about other central behavioral effects of ghrelin, and thus, we investigated the effects of ghrelin on anxiety and memory retention. The peptide was injected intracerebroventricularly in rats and we performed open-field, plus-maze, and step-down tests (inhibitory avoidance). The administration of ghrelin increased freezing in the open field and decreased the number of entries into the open spaces and the time spent on the open arms in the plus-maze, indicating an anxiogenic effect. Moreover, the peptide increased in a dose-dependent manner the latency time in the step-down test. A rapid and prolonged increase in food intake was also observed. Our results indicate that ghrelin induces anxiogenesis in rats. Moreover, we show for the first time that ghrelin increases memory retention, suggesting that the peptide may influence processes in the hippocampus.
Carlini
Valeria P
VP
Departamento de Farmacología, Facultad de Ciencias Químicas, Haya de la Torre y Medina Allende, Ciudad Universitaria, Universidad Nacional de Córdoba, 5016 Córdoba, Argentina.
Monzón
María E
ME
Varas
Mariana M
MM
Cragnolini
Andrea B
AB
Schiöth
Helgi B
HB
Scimonelli
Teresa N
TN
de Barioglio
Susana R
SR
D000818:Animals; D001007:Anxiety; D001069:Appetite Regulation / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D054439:Ghrelin; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D008124:Locomotion / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects; D036361:Peptide Hormones / Q000494:pharmacology* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D054439:Ghrelin; D036361:Peptide Hormones