Chronic Barbital Poisoning in the Rabbit.

Abstract

Clinically chronic barbital poisoning has been observed repeatedly. On the other hand no observations upon the effects of repeated injections of this drug upon animals seem to have been reported. The desirability of comparing similarities of symptoms in man and in laboratory animals is obvious.

At the start of a 12 week period rabbits were injected daily with a dose of 0.03 gm. of soluble barbital which was gradually increased to reach 0.15 gm. at the end of the period.

At the end of the 12 week period there were no appreciable changes in weight, heart and respiratory rates, appearance of the skin and hair coat, in the amount and character of stools, whereas the urine output seemed to be slightly diminished. There was undoubtedly a marked vasodilatation in the animals as evidenced by the congestion of the ears. At the end of the period the blood sugar level was found to be normal.

The most outstanding effects produced were upon the central nervous system. There was a marked increase of irritability and restlessness. They developed a very peculiar disturbance in gait. The movements of the fore limbs were quite normal. The hind limbs, however, showed a very decided backward thrust, such as one might expect were the rabbits attempting forceful movements on a very slippery surface. In this connection it should be recalled that in chronic barbital poisoning in human subjects one frequently sees cerebellar ataxy. The motor phenomena described above resemble the “rebound” seen in man.