The relationship between age and relaxation of vascular smooth muscle in the rabbit and rat.
نویسندگان
چکیده
Relaxation of rabbit and rat aorta by isoproterenol decreases with increasing age, whereas such responses caused by nitroglycerin or sodium nitrite are not age-dependent. In the present study, we sought to determine whether this relationship also exists in pulmonary arteries and portal veins. As was the case with the aorta, isoproterenol-induced relaxation of pulmonary arteries decreased as the animal aged; relaxation by nitroglycerin was minimally altered. Aging did not influence responses of rabbit and rat portal veins to isoproterenol or nitroglycerin. If the responses of these blood vessels are characteristic of the responses of other vascular smooth muscles to vasodilators, then this study suggests a difference in the manner by which arteries and veins age. We also confirmed that isoproterenol-induced relaxation of rabbit and rat aorta markedly decreases with increasing age and that the responses of rat aorta to nitroglycerin are independent of age. Because of the agonist used to contract the tissues prior to drug-induced relaxation, the results of the first series of experiments with nitroglycerin on rabbit aorta were at variance with our earlier findings. When KCl was used to contract the aortas, the mean effective dose (ED50) obtained for nitroglycerin for tissues from 2-year-old rabbits was 8 to 19 times larger than that obtained from 2-month-old rabbits. This ratio dropped to 4 when the tissues were contracted with histamine. Since KCl and histamine contract rabbit aorta by different mechanisms, this finding suggests that, in addition to a specific loss in beta-receptor activity, increasing age results in an alteration in the contraction-relaxation process of rabbit aortic tissue.
منابع مشابه
The role of autophagy in advanced glycation end product-induced proliferation and migration in rat vascular smooth muscle cells
Objective(s): To investigate the role of autophagy in advanced glycation end products (AGEs)-induced proliferation and migration in rat vascular smooth muscle cells (VSMCs).Materials and Methods: After culture, VSMCs were treated with 0, 1, 10, and 100 μg/ml concentrations of AGEs. Autophagy specific protein light chain 3 (LC3)-I/II was determined by western blotting, autophagosomes were observ...
متن کاملSaffron Induced Relaxation in Isolated Rat Aorta via Endothelium Dependent and Independent Mechanisms
Crocus sativus L. (saffron) is a widely used food additive for its color and taste. The hypotensive effects of saffron have been shown in previous studies. The aim of this study was to evaluate the mechanism of vasodilatory effects induced by saffron on isolated rat aorta.To study the vasodilatory effects of saffron aqueous extract (0.5, 1 and 2 mg/mL), isolated rat thoracic aorta rings were co...
متن کاملSaffron Induced Relaxation in Isolated Rat Aorta via Endothelium Dependent and Independent Mechanisms
Crocus sativus L. (saffron) is a widely used food additive for its color and taste. The hypotensive effects of saffron have been shown in previous studies. The aim of this study was to evaluate the mechanism of vasodilatory effects induced by saffron on isolated rat aorta.To study the vasodilatory effects of saffron aqueous extract (0.5, 1 and 2 mg/mL), isolated rat thoracic aorta rings were co...
متن کاملEffect of New Derivatives of Dihydropyridine on Rat Ileal Smooth Muscle in Vitro
In this research we evaluated the calcium channel antagonist activity of various diester analohues of nifedipine on rat ileal smooth muscle.in these analogues,the orthophenyl group at position 4 was replaced by 1 methyl 2-meythylsulfonyl or methylthio 5-imidazolyl.wistar rats(180-250g) were killed by a blow to the head.the intestine was removed above the ileucecal junction and longitudinal smoo...
متن کاملEffect of Subchronic Administration of Captopril on a1-Adrenoceptor Agonist-Induced Contraction of Isolated Aorta in Rat
Angiotensin II is a major endocrine hormone that affects directly both vascular smooth muscle and endothelial cells. Since vascular reactivity to angiotensin II changes in more physiological and pathophysiological conditions, the present study was performed to investigate the effect of intraperitoneal administration of angiotensin-converting enzyme inhibitor and captopril (30 and 50 mg kg-1, on...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Circulation research
دوره 38 4 شماره
صفحات -
تاریخ انتشار 1976