IMMUNOELECTRON MICROSCOPIC INVESTIGATION OF CREATINE-KINASE BB-ISOENZYME AFTER CEREBRAL-ISCHEMIA IN GERBILS

Alteration of creatine kinase BB-isoenzyme (CK-BB) was investigated in the vulnerable CA1 region of the hippocampus of ischemic and postisch emic gerbil brains using immunoelectron microscopy. CK-BB existed in t he neuronal perikarya, dendrites and axons as well as in astroglias in the normal gerbil brain. Immunocytochemical reaction products were as sociated with microtubules and polyribosomes. Propagation of ischemic and postischemic damage with disintegration of microtubules was observ ed in the dendro-somatic direction in neurons, which progressed in par allel with dispersion and loss of the immunocytochemical reaction for CK-BB in the dendroplasm. After reperfuson for longer than 24 h, CK-BB was also observed in the extracellular space. The present result supp orted the notion that loss of the immunohistochemical reaction for CK- BB which has been observed by light microscopy after cerebral ischemia , was at least partly due to dispersion of this enzyme caused by disin tegration of mirotubules and extracellular leakage of this enzyme, alt hough other processes, including degradation of CK-BB per se, were als o possible. The loss of CK-BB from the neuronal structure may delay th e recovery from ischemic damage and may eventually lead to neuronal de ath.