Contralateral cerebellar diaschisis 7 hours after MCA-occlusion in primates.

2,3,5-triphenyltetrazoliumchloride (TTC) as an indicator of mitochondrial function in combination with regional cerebral blood flow measurements was used in six baboons 6.9 +/- 1.2 h after permanent occlusion of the left middle cerebral artery. Staining with TTC was compared with blood flow data obtained during normocapnia using the microsphere method. Five animals showed a focal area of unstained tissue in the left middle cerebral artery territory. Mean blood flow in the unstained area was 28.3 +/- 15.4 ml min-1 100 g-1. Five of 6 animals showed a significant decrease of contralateral cerebellar blood flow in the presence of normal TTC staining. We conclude that at this early stage of infarction contralateral cerebellar diaschisis is caused by functional deactivation.