The Protective Effect of Mannitol and Methylprednisolone in the Acute Focal Cerebral Ischemia in Cats

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.