بررسي اثرات هيپركلسترولمي بر پاسخ هاي آيورت جدا شده رت به گشاد كننده ها و منقبض كننده هاي عروقي

Hypercholesterolemia Effects on Isolated Aortic Responses in Rats to Vascular Vasodilators and Vasoconstrictors

Atherosclerosis, mostly caused by hypercholesterolemia, is the most common cause of cardiovascular diseases in the world. Many studies with human and animal subjects have indicated that vascular responses to acethylcholine in atherosclerosis is significantly reduced. Different hypotheses have been proposed in the Atherosclerosis mechanism, but the exact mechanism is not clear. This study, therefore, is conducted to study the effects of hypercholesterolemia on cardiovascular parameters (including blood pressure, pulse, and vascular responses to vasodilators such as acetylcoline) and their probable mechanism in male rates. Hypercholesterolemia was induced by adding cholesterol (2%) to ratsʹ diet for 24 weeks. Blood sampler were abstained at the beginning and end of this period from ratsʹ eye sinus (1.5 ml). Arterial blood pressure and cholesterol level remarkably increased in subjects of the study and responses to acethylcholine significantly reduced. In vitro experimentation revealed that phenylephrine increased response in isolated aortic rings (from hypercholesterolemic male rats); while , acetylcholine decreased their responses administration of amniogounidine (100 mg/kg body weight , 2 hrs prior to thiopental injection) Significantly improved ratsʹ response to acetylcholine. Also, incubation of tissue with aminogouiding significantly increased the response to acetylcholine. Our findings revealed that activation of L- arginin nitric oxide pathway played a significant role in impaired vascular responses in hypercholesterolemia and that inhibition of this pathway can improve vascular responses to vasodilators such as acetylcholine.