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KMID : 0351819930340040349
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Kyunpook University Medical Journal
1993 Volume.34 No. 4 p.349 ~ p.356
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Central Effects of Losartan, an Angiotensin II Receptor Antagonist, on Responses to
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황경원
양은경/김형진/박재식/이원정
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Abstract
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This study performed to investigate effects of centrally administered angiotensin II (Ang II) receptor antagonist on the cardiovascular and vasopressin responses to hemorrhage.
Stainless steel cannula(22 gauge) was implanted stereotaxically in the lateral ventricle according to Paxinos' brain atlas. After a 5-day recovery period, bilateral femoral arteries and unilateral femoral vein were catheterized with PE50 tubing
filled
with heparinized saline. All surgical procedures were performed under pentobarbital anesthesia. On the following day, losartan (10 g/2 l), a nonpeptide AT1 receptor antagonist, or artificial cerebrospinal fluid(aCSF) was injected into the lateral
ventricle. Hemorrhage was performed 5 minutes after losartan injection at a rate of 3ml/kg/min for 5 or 7 minutes.
Intracerebroventricular(ICV) administration of losartan aggravated the fall of mean arterial pressure during hemorrhage, and significantly attenuated the recovery of the arterial pressure after hemorrhage. ICV losartan treatment also attenuated
the
tachycardiac response to hemorrhage during and after hemorrhage. Plasma vasopression concentration and renin
activity were increased 10 minutes after hemorrhage. This elevation for plasma vasopression concentration was significantly reduced in the losartan-pretreated group, but that of plasma renin concentration was greatly enhanced.
These results suggest that central Ang II through AT1 receptor plays an important physiological role in cardiovascular regulation and vasopressin release in responses to
hemorrhage.
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KEYWORD
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