Studies of the Role of Brain Melanocortin Receptors in Suppressing Food Consumption in Ether Stress in Mice

The melanocortin (MC) system controls food consumption in the resting state. Stress suppresses food consumption. It is not clear whether the brain MC system is involved in the development of stress anorexia in mice. The aim of the present work was to study the influences of pharmacological blockade and activation of brain MC receptors on food consumption on the background of stress. Mice (male C57Bl/6J) were subjected to ether stress (ether anesthesia for 0.5 min) before administration of physiological saline or a synthetic nonselective antagonist (SHU9119) or agonist (melanotan II) of MC receptors into the lateral ventricle. Food consumption in all mice was stimulated by prior 17-h starvation. Ether stress decreased food consumption and increased the blood corticosterone level and the hypothalamic AgRP gene mRNA (a natural antagonist of MC receptors) level 1 h after application. Pharmacological blockade of central MC receptors on the background of stress weakened stress anorexia and decreased the hypothalamic AgRP mRNA level, while activation exacerbated stress anorexia and hypercorticism. Thus, these studies showed that the central MC system is involved in the development of stress anorexia in mice.

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