1987 Volume 54 Issue 2 Pages 118-127
Nicardipine hydrochloride, which is one of the Ca2+ antagonists, was administered to two SHRSR (stroke-resistant spontaneously hypertensive rats) groups. In one group it was administered for 3 weeks (short-term T-SHR) and in the other for 8-10 weeks (long-term T-SHR). The degree of cerebral ischemia induced by BLCL (bilateral common carotid artery ligation) was investigated in the two groups as well as in two corresponding controls (U-SHR). The brain metabolites. (ATP, lactate, c-AMP) and brain water content were analysed 4h after BLCL, and histopathological changes were observed by scanning electron microscopy (SEM) 3h after BLCL. The influence. of duration of antihypertensive treatment and the ameliorating effect of the long-term treatment on experimental cerebral ischemia were discussed in this report.
ATP level in the short-term T-SHR group was higher than that in the U-SHR group after BLCL. However, there was no significant difference in lactate and c-AMP levels between these two groups. The brain water.content in the occipital region after BLCL in the. short-term T-SHR group was significantly lower than that in the U-SHR group, but there was no difference in the frontal region between the two groups. In the long-term T-SHR group, ATP and c-AMP levels were significantly higher than in the U-SHR group, and the lactate level was significantly lower. Furthermore the brain water content after BLCL in the long-term T-SHR group was significantly lower than in the USHR group in both the frontal and occipital portions. There was a more significant amelioration of the brain metabolism and brain edema after BLCL in the long-term T-SHR group than in the shortterm T-SHR group.
From the observation of SEM in the brain vessels after BLCL, the short-term and long-term TSHR groups showed less propagation of microvilli on the endothelial surface than either U-SHR group. Vasoconstriction was observed in these U-SHR groups. The marginal folds were shown to remain in both the short-term and long-term T-SHR groups after BLCL. However, in this histopathological study, the vascular endothelial ischemic changes of the brain vessels were much less in the long-term T-SHR group than in the short-term T-SHR group.
These results indicate that long-term antihypertensive treatment significantly contributed to the amelioration of ischemia.
