Age-related changes in contractile responses to noradrenaline in isolated blood vessels from rat and rabbit

1. Age-related changes in vascular function have been studied using rat (1, 6 and 10 months) and rabbit (1 and 6 months) isolated aorta and rat (1, 6 and 10 months) mesenteric perfused artery. 2. The EC50 values of noradrenaline in rat aorta increased with age. Similarly, contractile response to noradrenaline (10(-6) M) and potassium (80 mM) increased with age. In rabbit aorta, contractile responses, both for noradrenaline and potassium, decreased with age. No changes were observed with age in sensitivity to noradrenaline in rat mesenteric perfused artery. 3. The results of the present study suggest that age-related changes may be different for different blood vessels. The sensitivity decrease to noradrenaline in rat aorta involved postreceptor mechanisms.