Effects of S-adenosyl-L-methionine upon ischemia-induced brain edema in Mongolian gerbils and spontaneously hypertensive rats

Effects of S-adenosyl-L-methionine (SAMe).2 sulphate.tosylate upon the ischemia-induced brain edema and survival rate in Mongolian gerbils and spontaneously hypertensive rats were investigated, since SAMe is known to be important as a physiologically active substance in numerous metabolic processes including those that are inhibited in ischemia. SAMe suppressed increases in water and Na+ content in the ischemic brain which was produced by ligation of the common carotid artery for a short term (20-30 min) in Mongolian gerbils. This ameliorating effect of SAMe was observed dose-dependently at higher doses than 100 mg/kg administered repeatedly every 0.5 or 1 hr, starting within 2 hr, at least, after the reperfusion. Similar effects were also obtained in spontaneously hypertensive rats whose common carotid artery on both sides were ligated permanently. SAMe also increased survival rate in Mongolian gerbils with ischemic brain. Although the SAMe solution employed in the present experiments was hypertonic and contained mannitol as a filler, the beneficial effects were due to neither the hypertonicity of the solution nor mannitol, but due to SAMe itself.