Alterations in MAP2 immunostainability after prolonged complete brain ischaemia in the rat

Immediate loss of MAP2 immunostainability after very short ischaemic periods (3-5 min) has been reported in the gerbil. With longer periods of ishaemia this loss of immunoreactivity becomes identical with the pattern of ischaemia-induced selective neuronal injury. In contrast, in the four-vessel occlusion rat model, no such changes were observed during the early recirculation period. As no studies have focused on immediate changes due to complete brain ischaemia, we studied MAP2 immunoreactivity in the rat after cardiac arrest for up to 30 min. We observed a moderate decrease in stainability but the changes did not resemble those of selective vulnerability. We conclude that prolonged complete brain ischaemia without recirculation in the rat does not cause selective loss of MAP2 immunostainability in the vulnerable regions.