Reactivity of Small Vessels from Mature to Senescent Female Rabbits

Abstract

In order to determine if there are differences in reactivity of small arteries of cutaneous and skeletal muscle vascular beds taken from rabbits of different ages, vascular smooth muscle strips were tested in vitro with a variety of drugs. Arteries from the ear and hind limb skeletal muscle were removed from adult female rabbits, aged 6–48 months. Developed force of the vessel strips was measured during exposure to cumulative concentrations of norepinephrine, norepinephrine following propranolol, angiotensin II (skeletal muscle artery only) and histamine (ear artery only). Comparable segments of arteries from rabbits of different ages showed no significant differences in size or in maximum developed force attributable to age. A lack of beta-adrenoceptor activity was indicated in the ear arteries of all adult age groups studied, while propranolol enhanced contractile responses to norepinephrine in skeletal muscle arteries independent of age. Likewise, there were no consistent, age-related changes in the reactivity of either vessel type to norepinephrine, histamine, or angiotensin. This study indicates that small cutaneous and skeletal muscle arteries from mature female rabbits do not undergo any appreciable change in adrenergic and nonadrenergic sensitivity with age.