Inhibition of the vasomotor system of the anesthetized dog by epinephrine and norepinephrine.
نویسنده
چکیده
• Epinephrine, acting centrally, inhibits the •vasomotor system to produce vasodilatation.' This inhibition may be produced by a number of mechanisms, including stimulation of the sino-aortic baroreceptors, chemoreceptors,' and thoracic mechanoreceptors,and by blocking transmission in the vasomotor pathway at the sympathetic ganglia.The object of the following experiments was to determine the relative importance of these mechanisms in the anesthetized dog, to compare the actions of epinephrine and norepinephrine, and to find which blood vessels in the limb dilated and through which system of vasomotor nerves the dilatation was brought about. Methods Fifty-five dogs (7 to 16 Kg.) were anesthetized with sodium pentobarbital (Nembutal, 25 mg./Kg., injected intravenously), and the blood pressure was recorded from the femoral artery. One hind leg was separated from the body except for the sciatic nerve, the skin, muscle, and bone being divided. It was perfused through the femoral artery with oxygenated Krebs' solution contained in a resei-voir at a height of 200 cm. and passed through a heating coil at 37 C. to the cannula, The perfusion pressure was measured with a water manometer attached to a side arm of the cannula, and before each experiment the pressure was adjusted to about 50 em. by means of a clip between the heating coil and the cannula. Subsequent changes in perfusion pressure were due to alterations in the peripheral resistance of the limb and were brought about entirely through vasomotor fibers in the sciatic nerve.
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عنوان ژورنال:
- Circulation research
دوره 10 شماره
صفحات -
تاریخ انتشار 1962