Mori S, Kato M, Fujishima M
Department of Clinical Neurophysiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Hypertension. 1995 Apr;25(4 Pt 1):545-53. doi: 10.1161/01.hyp.25.4.545.
To elucidate the effects of prolonged hypertension on brain function during aging, we examined learning of an eight-arm radial maze task and local cerebral glucose utilization in young-adult (3 to 4 months old) and aged (16 to 17 months old) spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Young-adult SHR learned the task more slowly than young-adult WKY, but cerebral glucose utilization, measured by the [14C]2-deoxyglucose method in 24 brain structures, was not significantly different in the two groups. The aged SHR and WKY exhibited impaired learning ability. Cerebral glucose utilization was reduced (13% to 23%) in six regions in aged WKY and in 12 regions in aged SHR compared with values in the respective young-adult groups. Furthermore, the aged SHR showed a greater disturbance of learning acquisition and more profound reduction of cerebral glucose utilization in five regions than the aged WKY. In SHR, hypometabolism, indicated by a decrease in glucose utilization in 15 brain structures including the cerebral cortex, hippocampus, and visual system, was significantly correlated with impaired learning acquisition, indicated by an increase in total error choices. These findings show that (1) hypertension per se does not impair maze learning or cerebral glucose utilization in young-adult rats, and (2) brain function is impaired during aging and prolonged hypertension is an additional factor facilitating brain dysfunction associated with neuronal hypoactivities, resulting in behavioral deterioration including learning disability. Thus, early control of hypertension seems important for preventing or reducing brain dysfunction in senescence.
为了阐明长期高血压对衰老过程中脑功能的影响，我们检测了年轻成年（3至4个月大）和老年（16至17个月大）自发性高血压大鼠（SHR）及Wistar-Kyoto大鼠（WKY）在八臂放射状迷宫任务中的学习情况以及局部脑葡萄糖利用情况。年轻成年SHR学习该任务的速度比年轻成年WKY慢，但通过[14C]2-脱氧葡萄糖法在24个脑结构中测量的脑葡萄糖利用情况，两组间无显著差异。老年SHR和WKY均表现出学习能力受损。与各自年轻成年组的值相比，老年WKY的6个区域和老年SHR的12个区域的脑葡萄糖利用降低了（13%至23%）。此外，老年SHR在学习获取方面的干扰比老年WKY更大，且在5个区域的脑葡萄糖利用降低更显著。在SHR中，包括大脑皮层、海马体和视觉系统在内的15个脑结构中葡萄糖利用减少所表明的代谢减退，与总错误选择增加所表明的学习获取受损显著相关。这些发现表明：（1）高血压本身不会损害年轻成年大鼠的迷宫学习或脑葡萄糖利用；（2）衰老过程中脑功能受损，长期高血压是促进与神经元活动减退相关的脑功能障碍的一个额外因素，导致包括学习障碍在内的行为恶化。因此，早期控制高血压对于预防或减少衰老过程中的脑功能障碍似乎很重要。
