Cerebral Blood Flow, Glucose Utilization, Regional Glucose, and ATP Content during the Maturation Period of Delayed Ischemic Injury in Gerbil Brain

Abstract

Coupling between local perfusion and metabolism was examined in Mongolian gerbils during the development of delayed neuronal death using a combination of double-tracer autoradiography and imaging of local energy state. Animals were anesthetized with 1.5% halothane and forebrain ischemia was produced by occluding both common carotid arteries. After 5 min of ischemia, brains were recirculated for 6 h and 1, 2, or 4 days. At the end of the experiment, regional cerebral blood flow (CBF) and glucose utilization (CMRglc) were determined in identical brain sections with [131I]iodoantipyrine and [14C]deoxyglucose, respectively. Adjacent sections were taken for imaging of ATP and glucose using substratespecific bioluminescence reactions. In the CA1 subfield of control animals, CBF and CMRglc amounted to 81 ± 8 ml 100g−1 min−1 and 69 ± 2 μmol 100 g−1 min-1, respectively, and the calculated CBF/CMRglc ratio was 1.18 ± 0.12 ml/μmol (mean ± SD). After ischemia, the CBF/CMRglc ratio increased to 1.31 ± 0.14, 1.43 ± 0.16, 1.45 ± 0.16, and 1.56 ± 0.18 ml/μmol following 6 h and 1, 2, or 4 days recirculation, respectively. Glucose levels did not change during the 6 h to 4 day recirculation period in the hippocampal CA1 subfield. In the same region, ATP levels were unchanged during 6 h to 2 day postischemic recovery but reduced to about 70% after 4 days of recirculation. The results indicate that a mismatch of the flow-metabolism couple following transient ischemia does not appear to contribute to the postischemic maturation of delayed neuronal death in selectively vulnerable brain regions.