Effect of intravertebral angiotensin II on cardiac output and its distribution in conscious XXXX .

@entity235 @entity8 @entity51038
Intravertebral infusion of angiotensin II ( @entity51038 II) increases mean arterial pressure (MAP), but the contribution of cardiac output (CO) and total peripheral resistance (TPR) to this increase is unclear. In the present study, the effects of @entity51038 II infusion on CO and regional blood flow was determined by the microsphere technique in eight conscious, chronically catheterized @entity235 . @entity51038 II was infused into both vertebral arteries at 0.33 and 1.0 ng/kg/min, and intravenously at 0.66, 2.0 and 5.0 ng/kg/min. Intravertebral infusion of @entity51038 II at 0.33 ng/kg/min increased MAP by increasing CO without changing TPR or peripheral plasma @entity51038 II concentration. MAP also was increased with intravertebral infusion of @entity51038 II at 1.0 ng/kg/min, but this resulted from small increases in both CO and TPR. In contrast, intravenous infusion of @entity51038 II at 2.0 and 5.0 ng/kg/min increased MAP by increasing TPR in association with a decrease in CO. The increase in CO with intravertebral infusion of @entity51038 II at 0.33 ng/kg/min was distributed primarily to the muscles, kidneys, heart, and brain. Intravenous infusion of @entity51038 II at 5.0 ng/kg/min and, to a lesser extent, 2.0 ng/kg/min decreased blood flow to the skin, splanchnic region, and kidneys. These data indicate that the increase in MAP produced by a low intravertebral dose of @entity51038 II results from an increase in CO, which is distributed primarily to the muscle, kidney, heart, and brain. In contrast, the increase in MAP produced by a higher intravertebral dose of @entity51038 II results from increases in CO and TPR. This latter action is apparently due to a peripheral action of @entity51038 II to increase resistance in the skin, @entity8 .
