Time course of acute neuroprotective effects of lithium carbonate evaluated by brain impedanciometry in the global ischemia model

It is well known that chronic treatment with lithium gives cytoprotection from ischemia and neurodegeneration. Despite the clinical relevance, the potential effects of acute lithium treatment just before and during early stages of ischemia are not well known. Brain impedance was measured in an experimental global ischemia model, to determine these potential effects and their time course,as measured in minutes. Thiobarbital anesthetized (60 mg·kg–1, intraperitoneal injection) male Sprague–Dawley rats were infused intravenously (i.v.) with isovolumetric amounts of ringer (n = 10 rats) or lithium (Li2CO3; 10; 30; 100 mg·kg–1; n = 6 rats per dose tested). Cortico-subcortical impedance was recorded before (20 min) and after (20 min) the infusion, and during global cerebral ischemia (20 min) induced by cardiopulmonary arrest due to the administration of D-tubocurarine. Lithium did not change tissue impedance in normoxid animals. In the ringer-infused group, global cerebral ischemia first (9 min) shows a fast vo...