Renal vasodilatory response to intravenous glycine in the aging rat kidney.
Renal vasodilatory response to intravenous glycine in the aging rat kidney.
复制标题
衰老大鼠肾脏对静脉注射甘氨酸的肾血管舒张反应。
DOI：
10.1016/s0272-6386(12)80769-4
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Collins,R
中科院分区：
文献类型：
--
作者：
Baylis,C;Fredericks,M;Wilson,C;Munger,K;Collins,R
在清醒的、慢性插管的雄性SD大鼠上进行研究，以研究基线状态下的肾脏血流动力学，以及对大剂量静脉注射(IV)氨基酸(甘氨酸)的反应。研究对象为青年成年大鼠(3至4个月龄)、老年大鼠(18个月龄)和衰老大鼠(22至24个月龄)。肾脏的组织学评估允许结构和功能变化与年龄相关。组织学显示随着年龄的增长，进行性肾小球损害(硬化症)。18月龄大鼠肾小球滤过率正常，考虑到肾小球损伤程度(仅%正常肾小球)，应提示肾小球功能异质性，部分肾小球功能亢进。到22至24个月龄时(此时这种品系的雄性约有50%的死亡率)，肾小球滤过率显著降低，肾血浆流量(RPF)也显著降低。组织学上观察到严重的肾小球损害(只有34%的正常肾小球)，表明肾小球功能广泛的异质性。年轻的成年大鼠在急性静脉注射甘氨酸后表现出显著的肾血管扩张，这导致GFR和RPF增加了大约25%。肾血管对甘氨酸的反应性在18个月时减弱，在22至24个月龄的大鼠中完全消失。这种甘氨酸引起的肾脏血管扩张反应的改变可能既反映了与衰老相关的结构变化，也反映了由于衰老导致其他肾单位丢失，完整的功能亢进残余肾单位的代偿性血管扩张。
Studies were performed in the awake, chronically catheterized male Sprague-Dawley rat to investigate renal hemodynamics in the baseline state and also in response to a large intravenous (IV) amino acid (glycine) load. Studies were performed in young adult rats (age 3 to 4 months), old rats (age 18 months), and senescent rats (age 22 to 24 months). Histologic evaluation of the kidney permitted a correlation between structural and functional changes with aging. Histology showed progressive glomerular damage (sclerosis) with aging. In 18-month-old rats, the glomerular filtration rate (GFR) was normal, which, considering the level of glomerular injury (only 64% normal glomeruli), must indicate heterogeneity of glomerular function, with some hyperfunctioning glomeruli. By 22 to 24 months of age (at which time approximately 50% mortality has occurred in males of this strain), GFR is substantially reduced, as is renal plasma flow rate (RPF). Severe glomerular damage was observed histologically (only 34% normal glomeruli), indicating widespread heterogeneity of glomerular function. Young adult rats displayed a substantial renal vasodilation in response to acute IV glycine infusion, which resulted in approximately 25% increases in GFR and RPF. The renal vascular responsivity to glycine was diminished at 18 months and was completely absent in 22- to 24-month-old rats. This altered renal vasodilatory response to glycine probably reflects both structural changes associated with aging and also the compensatory vasodilation of intact hyperfunctioning remnant nephrons as other nephrons are lost due to aging.