Abstract
Injections of 20 to 30 μg. of 48/80 into the cerebral ventricular spaces of mice produced a condition of motor excitement termed “delirium ambulatorium.” This condition was aggravated by previous intraperitoneal injection of tranquillizers, atropine, and promethazine, not affected by previous injection of mepyramine and abolished by a previous injection of pentobarbitone. When an intraperitoneal injection of strychnine was followed by an intraventricular injection of 48/80, the strychnine convulsions became more violent, but the pattern of delirium ambulatorium was not produced.