Comparison of Effects of Angiotensin and Norepinephrine
نویسندگان
چکیده
T HE STUDY of responses to drugs is rewarding to the cardiovascular physiologist. Many agents evoke integrated responses that involve the heart, the pulmonary circulation, the systemic arteries, and the veins. The challenge is to dissect these responses into their component parts-to discover the contributions to the overall change made by alterations in cardiac function and vasomotor activity in various regions. In this way, a clearer view is obtained of the ways in which the cardiovascular system can adjust itself to new demands, both physiologic and pathologic. In addition, these particular stimuli, drugs, can be understood more fully and used for their specific properties. Norepinephrine and angiotensin are important, naturally occurring, potent pressor agents. While both raise the systemic arterial pressure, the integrated responses they evoke are quite different. These differences can be appreciated by examination of figures 1 and 2. The tracings represent the results of single rapid intravenous injections of these drugs into the femoral vein of an anesthetized, openchest dog. Systemic arterial pressure, pulmonary arterial pressure, and left atrial pressure are recorded with strain gauges. Blood flow in the descending thoracic aorta is measured with an inserted ultrasonic flowmeter. Let us assume, for purposes of this discussion, that thoracic aortic blood flow is pro-
منابع مشابه
Comparison of effects of angiotensin and norepinephrine on pulmonary circulation, systemic arteries and veins, and systemic vascular capacity in the dog.
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تاریخ انتشار 2005