Untersuchungen zur Differenzierung der durch 6-Aminonicotinamid, einem Antimetaboliten des Nicotinamids, hervorgerufenen zentralnervösen Funktionsstörungen

Summary

In rats, 6-aminonicotinamide (6-AN) lowers the body temperature, prolongs hexobarbital anaesthesia, increases the blood sugar concentration, and causes a loss of weight as well as extrapyramidal-motor disorders.

The threshold dosage for the lowering of body temperature after a single injection is about 5 mg/kg and 6 mg/kg if the total dose is divided into daily injections of 1 or 2 mg/kg. At a lower ambient temperature smaller doses are effective. Two weeks after the administration of 6-AN, body temperature is again within the limits of the normal values.

The duration of hexobarbital anaesthesia is prolonged by a threshold dose of about 5 mg/kg either in a single or in cumulative daily doses of 1 or 2 mg/kg. This effect had also disappeared after 2 weeks.

Hyperglycaemia reached its maximum within six hours p.i. and decreased to the normal glucose level within 16 hours p.i. after a single dose of more than 10 mg/kg of 6-AN. Smaller doses have no effect upon the blood sugar level.

When a total dose of 3 mg/kg 6-AN is administered, the body weight decreases. After the injection of 5 mg/kg the fall of body weight resembles that seen after starvation. Body weight starts increasing again after ten days.

Daily administration of low doses of 6-AN caused obvious spastic pareses and fine tremor of the extremities to appear without the usually observed intermediate stage of paralysis. The hind legs were not found to be preferently affected. This disturbance was more pronounced after 2 weeks than after 24 hours. The minimal effective dose for abnormal walking behavior lies in the range between 3 and 5 mg/kg.