ABSTRACT
@EN This study was performed to investigate the effects of central Ang Ⅱ on the hormonal responses to hemorrhage in conscious SHR and normotensive Wistar rats. 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 were catheterized. All Surgical procedures were performed under pentobarbital anesthesia. On the following day, Ang Ⅱ (30 ng/μl) or artificial
cerebrospinal
fluid (aCSF) was infused into the lateral ventricle at a rate of 2μl/min for 10 min. Acute hemorrhage (6ml/kg) was performed 5 minutes after infusion of Ang Ⅱ.
Intracerebroventricular administration of Ang Ⅱ produced a dose-dependent increase in blood pressure and decrease in heart rate. SHR showed a greater pressor response to central Ang Ⅱ than Wistar rats. Central Ang Ⅱ increased plasma
concentrations of
vasopressin, aldosterone and ANP, but decreased plasma renin activity. Acute hemorrhage produced a increase in plasma concentrations of vasopressin, aldosterone and renin activity, but a decrease in ANP level. Central Ang Ⅱ facilitated the
hemorrhage
induced increase in vasopressin release, but abolished the hemorrhage-induced increase in renin release. These results suggest that central Ang Ⅱ produces increase in blood pressure and facilitates hemorrhage-induced increase in plasma
concentration of
vasopressin. Therefore, these responses may contribute to facilitate the recovery from blood loss. (J Kor Endocrinol 8:141~148, 1993)
|