Inter-relation between hemodynamic, metabolic, ionic and electrical activities during ischemia and reperfusion in the gerbil brain

The aim of this study was to examine the inter-relation between the hemodyn amic events, energy metabolism, extracellular potassium and electrical acti vity during the acute phase of transient ischemia in the gerbil brain. It h as already been shown that partial ischemia in the gerbil brain causes chan ges in the blood flow, oxygen tension, electrical activity and potassium io n efflux. However, the description of the event during brain recovery from transient ischemia is not documented In order to enable a better understand ing of the pathophysiology during the ischemia as well as during reperfusio n, we used the multiparametric assembly system. This system enables simulta neous and continuous monitoring of CBF, intra-mitochondrial NADH, extracell ular potassium, DC potential and ECoG. Twenty anesthetized gerbils underwen t reversible carotid artery occlusion procedure for 3-4 min. While monitori ng the various parameters until complete recovery was reached, we found hig h correlation between the CBF and the NADH during occlusion as well as duri ng the reperfusion period However, CBF at the reperfusion period increased above the basal level while NADH returned to base line without an undershoo t, suggesting that the mitochondrial need for oxygen necessary for the prod uction of ATP is not the only factor influencing CBF during reperfusion. Fu rthermore, NADH returned to its normal level before extracellular potassium ion levels recovered to the baseline. This may suggest that ATP was no lon ger the limiting factor and ion pump activity became the factor determining and affecting the recovery processes.