Effects of clonidine on the experimental hypertension by abdominal aortic coarctation in rats

Cardiovascular baroreflex mechanisms and sympathetic tone could be involved in the arterial hypertension by coarctation of abdominal aorta artery (CoA). The present work analyzes the effect on the arterial pressure and heart rate (HR) of the clonidine, an α 2-adrenergic central acting antihypertensive agent, after intravenous (i.v.), intracerebroventricular (i.c.v.) and intrathecal (i.t.) administration in rats anesthetized with pentobarbital (40 mg/kg i.p.). Wistar rats of both sexes (240–270 g) were used to the 7 days of the CoA or a sham operation (SO). Values of mean arterial pressure (MAP) and of HR were calculated from intraarterial recordings of blood pressure. The MAP of the CoA rats (161.5±5.3 mmHg, n=20) was significantly higher ( P