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KMID : 0356619920070040364
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Journal of Korean Society of Endocrinology
1992 Volume.7 No. 4 p.364 ~ p.372
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Effects of Intracerebroventricular Angiotensin II on the Cardiovascular and Endocrine Systems in Conscious Normotensive and Hypertensive Rats
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안동국
오성태/양은경/박재식/이원정
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Abstract
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This study was performed to examine effects of central angiotensin II (Ang II) on blood pressure, heart rate and release of hormones, and to elucidate the mechanisms of pressor response to central Ang II in conscious Wistar and spontanously
hypertensive
rats (SHR). Stainless steel cannula (22 gauge) was implanted stereotaxically in the lateral ventricle according to Paxinos' brain atlas. Ang II (30 ng/μl) or artificial cerebrospinal fluid (aCSF) was infused into the lateral ventricle through
the
cannula at a rate of 2 μl/min for 10 min.
Intraventricular administration of Ang II produced a dose-dependent increase in blood pressure. SHR showed a greater pressor response to central Ang II than Central Ang II produced approximately 6 fold increase in plasma concentration of
vasopressin,
and less than 50% increase in plasma concentrations of aldosterone and atrial natriuretic peptide(ANP). But plasma renin activity was decreased by central Ang II. Changes in plasma hormonal levels were not significantly different between Wistar
and
SHR
Vasopressin receptor antagonist (V1) partially abolished the pressor response to central Ang II. However. In rats pretreated with pentolinium. V1 receptor antagonist completely blocked the pressor response of central Ang II. When baroreflex
sensitivity
was tested by the method of quick hemorrhage 6( ml/kg). central Ang II attenuated the baroreflex sensitivity. These results suggest that pressor response toi cnetral Ang II is mediated by the activation of sympathetic nervous system and by
release
of
vasopressin in pressor amount. In SHR, central Ang II produced a greater pressor action but attenuated the baroreflex sensitivity. (J Kor Soc Endocrinol 7:364~372, 1992).
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KEYWORD
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