Abstract

• It is the purpose of the this experimental study to investigate the protective effect of pretreatment of mannitol and methylprednisolone(MP) on the changes of the high-energy metabolites(nucleotides ; derivatives of adenosine, guanosine, uracil and cystosine) and adenylate energy charge in the brain tissue of the cats. The experimental animals were divied into three groups. Group I was the sham control groups that the postorbital approach was performed but no occlusion of MCA. Group II was the recirculation group that of 2-hour recirculation after the occlusion of the middle cerebral artery(MCA) via the postorbital approach. Group III was that of pretreatment of the combination of mannitol(29mg/kg) and MP(3mg/kg) at 30 minutes before occlusion of the MCA and then every one and a half hours during the 5-hours occlusion and 2-hours recirculation. The experimental results are as follows. 1) Adenosine derivatives : In group III ATP was significantly increased to 622.9%, ADP significantly increased to 154.81%, AMP reduced 68.05% and total adenosine nucleotides increased to 103.63% of the values of group III. 2) Adenylate energy charge(E.C.) : In group III E.C. was recovered to 82.66% and increased to 206.66% of the values of group II. 3) Guanosine derivatives : In group III GTP was significantly increased to 554.03%, GDP increased to 96.61% and GMP reduced to 62.71% of the group II. 4) Uracil derivatives : In group III UTP and UDP was significantly increased to 470.37%, and 300.64% respectively and UMP was reduced to 91.7% of values of group II. 5) Cystosine derivatives : In group III CTP was increased to 133.33%, CDP reduced to 90.0% and CMP increased to 119.03% of values of group II. These above results suggested that pretreatment of mannitol and MP have a protective effect on the acute focal cerebral ischemia when given prior to the onset of the ischemia by the stabilization of the energy regulation and maintenance of a higher level of adenylate E.C.