Systemic clonidine increases feeding and wheel running but does not affect rate of weight loss in rats subjected to activity-based anorexia.

Activity-based anorexia (ABA) is an animal model of anorexia nervosa with two characteristics of the disorder, decreased food intake and increased activity. We have shown that chronic noradrenergic stimulation of the paraventricular hypothalamus exacerbates ABA rather than ameliorates it. This study determined if peripheral chronic administration of clonidine affects ABA. Rats were implanted SC with osmotic minipumps infusion 0, 30, or 300 micrograms/kg/day of clonidine and exposed to ABA (1.5 h/day ad lib food, 22.5 h/day ad lib wheel access). Results showed that clonidine did not affect the rate of weight loss during ABA, but increased food intake at the lower dose and wheel activity at the higher dose. It is proposed that increased energy expenditure due to wheel running is counteracted by an inhibition of sympathetically mediated diet-induced thermogenesis, and that the elevation in running by the higher dose potentially increases the risk of developing ABA.