Stimulation of 5‐HT1A receptors of the PVN with inhibition of HPA axis on feeding

Abstract

5‐HT1A Receptor is expressed in the paraventricular nucleus of the hypothalamus (PVN), where corticotropin release hormone is located release and synthesis, stimulation of 5‐HT1A receptor of the PVN was described to produce an increase of CRH in rats due probably stimulation of HPA. The aim of the present study was characterize the stimulation of 5‐HT1A receptor of the PVN with inhibition of HPA axis on feeding. Male Wistar rats, with 250–300 g were accustomed to a diet of separate sources of protein, carbohydrate and fat, and then were implanted a cannula on right PVN, a second surgery to identified (sham) or remove the adrenal glands bilaterally (ADX) were done. After post‐surgery recovery (5 days), rats were assigned to a group and a treatment: sham (saline solution), sham+agonist 8‐OH‐DPAT, sham+WAY 100635, sham+WAY100635+8‐OH‐DPAT, ADX (saline solution), ADX+8‐OH‐DPAT, ADX+WAY 100635, ADX+WAY 100635+8‐OH‐DPAT. Continuous record of 60 min was made for analyse the behavioral satiety sequence (BSS). The results showed that ADX decrease food intake. Administration of 8‐OH‐DPAT decrease carbohydrates and fat intake in sham groups. Pretreatment with WAY 100635 prevent hypophagic effect. BSS reveal that 8‐OH‐DPAT delay the natural development pattern of satiety. Administration 8‐OH‐DPAT increases glucose serum concentration. Agonist 8‐OH‐DPAT decrease food intake of carbohydrates in ADX groups. ADX rats interrupt the natural pattern of BSS. Finally is possible to suggest that HPA axis must be intact for the integration of signals between serotoninergic and CRH to control food intake and BSS.