Tamaki K, Nakai M, Yokota T, Ogata J
National Cardiovascular Research Institute, Osaka, Japan.
Gerontology. 1995;41(1):11-7. doi: 10.1159/000213657.
We measured regional cerebral blood flow (rCBF) in young and old Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats by a minimally invasive microsphere technique. Blood flows to the cerebrum, diencephalon, mesencephalon, cerebellum and pons-medulla during normocapnia were determined. To test the ability of the vessels to dilate, rCBF was also measured during hypercapnia. Reactivity to CO2 was calculated as delta rCBF/delta paCO2. In the old SHR, blood flow to the pons-medulla (88 +/- 8 ml/min/100 g, mean +/- SEM) was markedly lower than that in the young SHR (107 +/- 4 ml/min/100 g, p < 0.05), whereas the difference of those values in the old and young WKY rats was slight (0.05 < p < 0.1). There were no differences in the values of blood flow to the cerebrum, diencephalon, mesencephalon or cerebellum between the young and old rats in both species. Cerebrovascular CO2 reactivity was markedly impaired in the old SHR (p < 0.05) compared to that in the young SHR, but the difference in reactivity in the WKY rats was not significant. The results indicate that blood flow to the pons-medulla is reduced in association with age, particularly in the hypertensive animals, and that the ability of the cerebral vessels to dilate is impaired homogeneously by the combination of chronic hypertension and aging.
我们采用微创微球技术测量了年轻和老年Wistar-Kyoto（WKY）大鼠及自发性高血压（SHR）大鼠的局部脑血流量（rCBF）。测定了正常碳酸血症期间大脑、间脑、中脑、小脑和脑桥-延髓的血流量。为了测试血管舒张能力，还在高碳酸血症期间测量了rCBF。CO2反应性计算为ΔrCBF/ΔpaCO2。在老年SHR中，脑桥-延髓的血流量（88±8 ml/min/100 g，平均值±标准误）显著低于年轻SHR（107±4 ml/min/100 g，p<0.05），而老年和年轻WKY大鼠的这些值差异较小（0.05<p<0.1）。在这两个物种的年轻和老年大鼠之间，大脑、间脑、中脑或小脑的血流量值没有差异。与年轻SHR相比，老年SHR的脑血管CO2反应性明显受损（p<0.05），但WKY大鼠的反应性差异不显著。结果表明，脑桥-延髓的血流量随年龄增长而减少，尤其是在高血压动物中，并且慢性高血压和衰老共同作用会使脑血管舒张能力均匀受损。
