Effects of Swim Training on Blood Pressure, Catecholamines and Prostaglandins in Spontaneously Hypertensive Rats

Abstract

A 6-month program of exercise with a daily swimming time of 30 minutes 3 times a week was carried out in female spontaneously hypertensive rats (SHR) to assess the roles of catecholamine and prostaglandin metabolism in the antihypertensive effect of chronic exercise conditioning. Swim training resulted in a significant reduction of mean blood pressure in SHR by 13.3 mmHg as compared with sedentary controls (158.8±5.0 versus 172.1+3.3 mmHg, p<0.05). The increase in plasma levels of norepinephrine and epinephrine after acute blood loss of 2% of body weight were smaller in trained than control SHR. The daily urinary excretion of thromboxane By, a stable metabolite of thromboxane A2, was significantly decreased by 33% in swim trained SHR as compared with control SHR (p<0.01), while there was no difference in urinary excretion of prostaglandin E2 or 6-keto-prostaglandin Fio, a stable metabolite of prostacyclin. These findings indicate that both the suppression of the sympathoadrenal system and decrease in vasoconstrictory prostaglandins in the kidney may have shared in the antihypertensive effect of exercise training in SHR. (Jpn Heart J 35: 205-211, 1994). © 1994, International Heart Journal Association. All rights reserved.