抄録
Dialysis tubing with a 0.2-mm diameter was implanted into the caudate nucleus of spontaneously hypertensive rats. Continuous perfusion with Ringer's solution at a flow rate of 10 μl/min was then initiated. During incomplete cerebral ischemia induced by bilateral common carotid artery occlusion, the perfusate was collected every 20 minutes and analyzed for the content of monoamines and their metabolites. The extracellular content of dopamine was abruptly increased about 4 to 6 minutes after ischemic insult, reached a maximum after about 20 to 40 minutes, and then decreased over 120 minutes. During the same period, 3, 4-dihydroxyphenyl acetic acid and 5-hydroxyindole acetic acid were significantly decreased, and 5-hydroxytryptamine was not detected during the ischemic period. The results suggest that the ischemia induced a large increase in extracellular dopamine within the caudate nucleus and that leakage occurred due to the energy failure of cell membranes. This process may be one causal factor in the neuronal damage observed after ischemia.
