Analysis of the changes in brain organic osmolytes in cerebral ischemia

点击翻译按钮获取中文摘要

The cell volume is regulated not only by inorganic ions, but also by organic osmolytes, such as amino acids, methylamines, and polyhydric alcohols (polyols). Using proton nuclear magnetic resonance spectroscopy (^1H-NMR), we measured the tissue concentrations of those organic osmolytes in the rat brain after middle cerebral artery occlusion (incomplete focal ischemia) or after decapitation (complete global ischemia). The total osmolytes expressed as a sum of total amino acids, total methylamines, and total polyols were significantly decreased at 24 hours of focal ischemia (58.7% of control value, P=0.0025) whereas they were not changed following decapitation. The water content was increased from control value of 77.9% to 84.1% after focal ischemia (P<0.0001) bit not after decapitation. These results suggested that the brain organic osmolytes are involved in the process of edema formation following focal cerebral ischemia. Further elucidation of the cellular mechanisms regulating these organic osmolytes in cerebral ischemia may promote greater understanding of pathophysiology of brain edema as well as the development of novel measures of treatment.