摘要
目的 探讨老年大鼠（１９～２２ 月龄） 皮层肾小球毛细血管对外源性血管紧张素Ⅱ（ＡＮＧⅡ） 的敏感性。方法 利用活体微穿刺技术。结果 在年轻大鼠，ＡＮＧⅡ导致肾血浆流量（ＲＰＦ）和肾小球血浆流量（ＱＡ） 下降，伴随肾小球血压（ＰＧＣ） 和肾小球静水压梯度的升高，而肾小球毛细血管超滤系数（Ｋｆ） 基本不变，所以，不改变肾小球滤过率（ＧＦＲ） 和单个肾单位ＧＦＲ（ＳＮＧＦＲ） 。在老年大鼠，ＲＰＦ和ＱＡ 下降，ＰＧＣ升高，Ｋｆ 显著下降，ＧＦＲ和ＳＮＧＦＲ显著下降。ＡＮＧⅡ在老年和年轻大鼠引起相同程度的入球和出球动脉阻力（ＲＡ，ＲＥ）和ＰＧＣ升高。结论 老年和年轻大鼠的入球和出球小动脉对ＡＮＧⅡ有相同的敏感性，而老年大鼠Ｋｆ 对ＡＮＧⅡ更敏感而导致ＳＮＧＦＲ的显著下降。
Objective To investigate the sensitivity of the cortical glomerular microvasculature of the old rat kidney to exogenous angiotensin Ⅱ (ANGⅡ). Methods Using the in vivo micropuncture technique in SD rats. Results In the baseline state, glomerular blood pressure (P GC ) in old male rats was higher compared to young rats. During exogenous ANGⅡ infusion, a significant rise in arterial pressure and renal vasoconstriction occurred in both old and young rats. In young rats, the ANGⅡ induced a fall in renal plasma flow (RPF) and glomerular plasma flow (Q A) was accompanied by a rise in P GC and thus the glomerular hydrostatic pressure gradient, with little change in glomerular capillary ultrafiltration coefficient (K f ). Therefore, the glomerular filtration rate (GFR) and single nephron GFR (SNGFR) were unchanged. In old rats, RPF and Q A fell, a rise occurred in P GC and also a fall was seen in the K f thus GFR and SNGFR fell significantly. The magnitude of pressor and renal vasoconstriction response to ANGⅡ were not affected by age; ANGⅡ increased afferent and efferent arteriolar resistance (R A,R E) and P GC by similar amounts in young and old rats. Conclusion The afferent and efferent arteriols had similar sensitivity to exogenous pressor dose of ANGⅡ in both young and old rats, but K f was more sensitive to ANGⅡ in old rats leading to significant fall in SNGFR.
出处
《中华肾脏病杂志》
CAS
CSCD
北大核心
1999年第6期347-350,共4页
Chinese Journal of Nephrology
基金
美国国立卫生研究院基金!(NIH) (No .HL31933)
关键词
肾小球滤过率
肾血浆流量
肾小球血压
ANGⅡ
Glomerular filtration rate Renal plasma flow Glomerular blood pressure Glomerular ultrafiltration coefficient
