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pubmed:abstractText |
A method for the perfusion of the isolated brain of the rat with synthetic fluorocarbon emulsion is described. The functional states of the brains were investigated using biochemical, biophysical, and histological methods. After 4.5 h of perfusion, all brains were in excellent condition and comparable to the in vivo state. The influence of perfusion conditions on the viability of the brains was studied. Deep hypothermia was well tolerated; at 13 degrees the EEG exhibited a mean frequency of about 8 Hz, while the mean amplitude was about 40% lower than at 28 degrees or 36 degrees. Constant-pressure perfusion did not affect brain function, provided that the pressure amplitude was very slowly decreased. During application of pentylenetetrazole (PTZ) it was found that the threshold concentration of PTZ in the perfusion medium to induce epileptic seizure discharges was 0.13 mg/ml. However, after repeated application of PTZ, the threshold concentration decreased exponentially, indicating a kindling phenomenon. It could be shown that not PTZ as such, but the spike potentials provoked by PTZ, induced the kindling effect. This was inhibited by application of primidone or phenobarbital.
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