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3 min after simultaneous i.v. administration of phenazone (200 mg/kg) and of pentetrazole (50 mg/kg) or of phenazone and of the convulsively active S-(+)-1-methyl-5-phenyl-5-propyl barbituric acid = (+)-MPPB (75 mg/kg), respectively, phenazone concentrations in liver, spleen and fat tissue of rats are lower, in brain tissue, however, it is higher than those of the control (rats receiving phenazone only); the distribution pattern of (+)-MPPB between the tissues corresponds to that of phenazone after simultaneous administration of pentetrazole. In rats anaesthetized by hexobarbital (35 mg/kg) or by the anaesthetically active R-(-)- 1-methyl-5-phenyl-5-propyl barbituric acid = (-)-MPPB (75 mg/kg), respectively, phenazone tissue distribution is at the same time (3 min) not different from that of the control; the tissue distribution pattern of (-)-MPPB corresponds to that of phenazone after simultaneous administration of hexobarbital. Following pretreatment with diazepam, reserpine and phenoxybenzamine, respectively, the tissue distribution pattern of (+)-MPPB, in the rats approaches that of (-)-MPPB. The distribution of (-)-MPPB in the tissues corresponds to that of (+)-MPPB, if the animals receive simultaneously pentetrazole or are electrically stimulated, respectively, to cause a convulsive seizure.

The influence of corticosteroids on the tone of isolated smooth muscle (vas deferens of the rat) is reported. Corticoids alone are without effect on the muscle tone, but they potentiate the constrictor effect of catecholamines. Fluorinated synthetic steroids exhibit a more pronounced effect than non-halogenated ones.