The Effect of Chronic Exercise on Vascular and Kidney Responses to Angiotensin II in the Wistar Kyoto rat (WKY)

Hypertension, or high blood pressure, is believed to result, in part, from the kidney\u27s failure to remove excess sodium and water from the body. Angiotensin II is a hormone that is involved in sodium and blood pressure regulation. If angiotensin II levels are increased, the blood pressure will greatly increase. Likewise a decrease in angiotensin II results in lower blood pressure. Exercise can reduce blood pressure.The mechanism by which exercise lowers blood pressure is unclear. It is possible that exercise lowers the body\u27s response to angiotensin II, thus decreasing blood pressure. The current study investigates the effect of regular exercise on the kidney and blood pressure responses to angiotensin II. Rats were randomly placed into either an exercise group ( from weaning to 12-14 weeks of age), or a sedentary group (no exercise). Voluntary exercise time and running distance were recorded daily. At 14 weeks of age, rats were anesthetized (Inactin, 1 00mg/kg). A breathing tube was placed in the trachea, and cannulas were inserted into the carotid artery (to monitor blood pressure and heart rate), the jugular vein (to infuse saline to maintain fluid balance), and into the bladder for urine collection. Angiotensin II was intravenously infused while blood pressure and urine sodium excretion were monitored. Results were compared between the exercised and sedentary groups