Session: 7

PS7-14 | Enriched environment reduces food intake and body weight modulating the hypothalamic NPY/GHSR system.

Rocio Schumacher

Grupo de Neurobiología del Instituto de Salud y Ambiente del Litoral, Universidad Nacional del Litoral-CONICET.

The enriched environment (EE) is a model of inanimate and social stimulation that reduces adiposity and improves glucose tolerance and eating behavior. Our objective was to study the effects of EE on the brain homeostatic system that regulates food intake. For this, male Wistar rats were exposed on postnatal day 21 (PND) to EE (collective cage of 14 rats with different toys, n=14) or standard environment (SE, cage of 4 rats without toys, n=14). Body weight and food intake were monitored weekly until sacrifice at PND90, when the weight of epididymal adipose tissue (EAT) and brain were obtained. The arcuate nucleus (ARC) of hypothalamus was isolated using the Palkovits micro-punch technique. The gene expression of orexigenic neuropeptides [Agouti related protein (AgRP) and neuropeptide Y (NPY)], anorexigenic neuropeptides [amphetamine and cocaine regulated transcription (CART) and proopiomelanocortin (POMC)] and leptin (Ob-Rb) and ghrelin (GHSR) receptors were measured by RT-PCR. The results showed that the EE group presented a reduction in food intake after the first week and a lower body weight from the second week of the experiment. At PND90, the EE group had 7% less body weight (p=0.0004) with no differences in the EAT. In ARC, the EE group presented lower levels of expression of NPY (p=0.034) and GHSR (p=0.019). In conclusion, EE disrupts the NPY/GHSR system and alters the homeostatic regulation of food intake, leading to a decrease in food intake and body weight.