Influence of time interval between administration of chloramphenicol and thiamylal on the sleeping time of mice.

The influence of the time interval between chloramphenicol and thiamylal administrations on the sleeping time of mice was studied. Two hundred 20- to 25-g mice were given (intraperitoneally) chloramphenicol or isotonic saline solution and then thiamylal at different time intervals between drugs. The duration of anesthesia was measured as the time between the loss and the return of the righting reflex. The results indicated that in mice given chloramphenicol simultaneously with thiamylal (0 time interval), the sleeping time was increased by a factor of about 10 as compared with the sleeping time in mice given thiamylal alone. As the time interval between administrations of thiamylal and chloramphenicol was increased (from 0.25 to 4 hours), the prolongation of sleeping time decreased correspondingly.