Fluoxetine and Venlafaxine effect on food intake and reward gene expression in depression animal model

MARIA BELEN PORETTI; MARTA FIOL DE CUNEO; VALERIA PAOLA CARLINI

Córdoba

Congreso; XIII Jornada de Investigación Científica de la Facultad de Ciencias Médicas; 2012

Secretaría de Ciencia y Tecnología. Facultad de Ciencias Médicas. UNC

Fluoxetine and Venlafaxine effect on food intake and reward gene expression in depression animal model Poretti MB,  Fiol de Cuneo M and Carlini VP. Cátedra de Fisiología Humana, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba. Depression and antidepressant treatments often affects food intake; there are studies showing that depression and obesity are associated. But we still do not know if depression leads to an increase in food intake which could lead to obesity, or if the individual becomes depressed after being overweight. The aim of this work is to study in hypothalamus the expression of genes related with food intake in a depression animal model (bilateral olfactory bulbectomy) and after fluoxetine (F) and venlafaxine (V) treatment, two monoamine re-uptake inhibitors. Adult male Albino?s Swiss mice were divided in two groups: without bulbetomy group (Sham) and bulbectomized group (OB). Both groups were orally treated, during 28 days with saline (S), F (10 mg/Kg/day) or V (10 mg/Kg/day), n=10 animals/group. The food intake and body weight were daily measured and in order to determine a depressive behavior the tail suspension test was applied. The last day of treatment the mice were sacrificed and their hypothalamus was collected by dissection, in order to study the expression of genes using real time PCR. The genes analyzed include dynophin synthesis, kappa-opioid receptor (KOR), my-opioid receptor (MOR) and delta-opioid receptor (DOR). Food intake and the body weight gain significantly decreased in OB-S animals with respect to Sham-S (cumulative food intake OB-S=115.75 ± 3.06 vs. Sham-S=131.17 ± 2.52; p<0.001). The fluoxetine and venlafaxine treatment significantly reverts this effect (p<0.001). The gene expression of dynorphin was significantly higher in OB-S than Sham-S (relative expression (AU) OB-S= 2.23 ± 0.03 vs Sham-S= 1.21 ± 0.01; p<0.001). Fluoxetine treatment elicited a significant decrease in dynorphin expression in OB animals with respect to OB-S (AU OB-F= 1.35 ± 0.02 vs. OB-S= 2.23 ± 0.03; p<0.001). The gene expression for KOR and MOR was decreased in OB-F when compared with OB-V (p<0.01). The OB-S animals showed a significant increase in the immobility time in TST. The treatment with F or V reverts this effect (p<0.001). Taking in account that dynorphin system generally promotes anxiety-like behavior and affect feeding, it is possible to suggest that the increment in the expression of this gene in hypothalamus could explain the reduction in food intake and body weight gain in OB-S animals.