[Superior protective activity of phenytoin against hypoxia in pharmacological screening test].

In the treatment of cerebral infarction, it is important to select drugs for inhibiting development of the pathology. In order to select markedly effective drugs among many drugs, it is possible to grasp the outline of drug effects by means of an experimental system with simplicity and regularity--a screening test. In the present study, we induced a hypoxic load by exposing mice to a gas mixture consisting of 4% O2 and 96% N2, and investigated the effects of various kinds of drugs with reference to the survival time(ST: mean +/- SE), the time until the respiratory arrest of the mice. In the control group (n = 110), ST was 170 +/- 6 sec, with a normal distribution, and no mice that survived for eight minutes or more after the load were found. In contrast, ST was 1,833 +/- 487 sec in the suloctidil-treated group (12.5 mg/kg, n = 11), 1,160 +/- 342 sec in the vitamin E group (200 mg/kg, n = 15), 602 +/- 74 sec in the pentobarbital group (50 mg/kg, n = 12) and 2667 +/- 452 sec in the phenytoin group (100 mg/kg, n = 10). On the other hand, no prolongation of ST was found in the groups to which vitamin C, coenzyme Q, cytochrome c, betamethasone, mannitol or germanium-132 were administered. The ratio of the mice that survived for one hour or more after the load was 0% in the control group, 45.5% in the suloctidil group (12.5 mg/kg), 23.5% in the vitamin E group (200 mg/kg), 0% in the pentobarbital group (50 mg/kg) and 70% in the phenytoin group (100 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)