Effect of Nimodipine on Incomplete Global Cerebral Ischemia-Reperfusion with prior Hyperglycemia: in vivo 31P Magnetic Resonance Spectroscopic Study in Cats

Park, Pyung Hwan; Lee, Yu Mee; Choi, Jong Moo

Abstract

In vivo 31P magnetic resonance spectroscopy (MRS) was used to evaluate the effect of nimodipine on changes of [H] (pH) and the ratio of [PCr]/[Pi] in cats subjected to an incomplete global cerebral ischemia-reperfusion under the pretreated condition of hyperglycemia. Animals were subjected to a transient (18 minutes) incomplete global cerebral ischemia; the systemic arterial hypotension was induced, and immediately followed by the bilateral carotid artery ligation. Twenty cats were divided into 3 groups; for group 1 (control), 7 cats were employed for a control group; for group 2 (hyperglycemia), 7 cats were a hyperglycemia group with infusion of 50% glucose prior to ischemia; for group 3 (Nimodipine), 6 cats were infused with 50% glucose prior to ischemia, and nimodipine after ischemia. The time course of changes in pH and [PCr]/ [Pi] was monitored before, during and after ischemia. The pH decreased immediately after ischemia in all three groups. After the reperfusion was made, the values of the pH did not retum to the baseline value for the group 2 (hyperglycemia) and 3 (nimodipine), in contrary to the group 1 (control). The ratio of [PCr]/[Pi] was dropped to 20% of the baseline value after ischemia in all three groups. The value was recovered progres- sively during reperfusion period for group 1 (control), whereas for group 2 (hyperglycemia) and group 3 (Nimodipine) the values were remained depressed. The results suggest that the condition of hyperglycemia induced by the infusion of 50% glucose prior to the incomplete global cerebral ischemia-reperfusion, may deteriorate the cerebral ischemia and the infusion of nimodipine during ischemia-reperfusion has no beneficial effects to improve the cerebral acidosis and the metabolic recovery.