A qualitative study on changes in local brain pH due to discrete cerebral microembolism

In this work autoradiography of 14C-5,5-dimethyl-2,4-oxazolidinedione (14C-DMO) was used to trace changes in local cerebral pH in embolized awake rabbits. One hour after i.v. injection of 14C-DMO small cerebral ischemic foci were produced in rabbits by injecting plastic beads into the left heart ventricle under short-acting anaesthesia, and after another hour the animals were put to death and their brains processed for autoradiography of 14C-DMO. Evidence of acidosis was in general not found in the microischemic regions, though there were a few possible exceptions. However in the hippocampus a diffuse acidosis involving a large part of the structure, could be found in 2 of the 4 experiments. This hippocampal phenomenon probably reflected the same process as has been observed using autoradiography of 2-deoxyglucose (reflecting cellular glucose uptake) on the same ischemic model increased 2-deoxyglucose phosphorylation. Because the hippocampus is involved in the memory function and the fact that small infarcts are coupled to dementia, this phenomenon should be drawn into focus for further studies.