IschemiaMyocardial IschemiaBrain IschemiaReperfusion InjuryMyocardial Reperfusion InjuryIschemic Attack, TransientReperfusionWarm IschemiaCold IschemiaIschemic PreconditioningGerbillinaeSpinal Cord IschemiaTime FactorsDisease Models, AnimalMyocardiumRats, Sprague-DawleyIschemic Preconditioning, MyocardialRats, Wistar