To evaluate the effect of nimodipine on the size of infarction and regional cerebral blood flow (rCBF), focal cerebral ischemia was produced by middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. The experimental groups were divided
into a
saline-treated (control) group and a nimodipine-treated group. The rats in the nimodipine-treated group were intravenously loaded with 10μg/kg of nimodipine 30 min before MCAO and infused with a speed of 1μg/kg min over next 1 hour by an
infusion
pump
and the rats in the control group were given the same volume of saline by the same method. The sizes of infarction were measured by staining the coronal sections of the brain with 2% 2,3,5-triphenyltetrazolium chloride (TTC0 solution and the
regional
cerebral blood flows (rCBFs) were clculated by an sutoradiography using 14C iodoantipyrine.
The results were summarized as follows :
1. Arterial blood pH, PCO2, PO2 and blood glucose level determination were done just after MCAO. There were no significant differences between the two groups.
2. Arterial blood pressure was monitored from 30 minutes before to 30 minutes after MCAO e4very 5 min. there were no significant changes of blood pressure in both groups.
3. The sizes of infarction were measured and compared between the two groups by TTC staining. The sizes of infarction were singificantly decreased in the nimodipine-treated group (p<0.05).
4. Regional cerebral blood flows in the nimodipine-treated group were singificantly improved in the the areas neighboring to the dense ischemic core, somatosensory area of frontal and parietal lobes. The areas which showed a significant
imporovement in
the rCBF were the motor areas of frontal and parietal-cortices, caudate head, anterior caudoputamen, amygdala, CA3 area and auditory cortex.
5. The serial measurement of rCBF of cerebral cortex with 1 mm's interval showed a significant improvement of rCBF in the areas neighboring to the ischemic core in te nimodipine-treated group (p<0.05).
6. The area withthe rCBF under 25ml/100g/min was significantly decreased in nimodipine-treated group in the analysis according to the critical cerebral blood flow (p<0.050.
In summary, these results indicate that the pretreatment with nimodipine reduced the size of infarction and improve the rCBFs in the focal cerebral ischemia of Sprague-Dawley rats.
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