Behavioral and biochemical effects of the carbamate insecticide, MOBAM

Decreases in rat plasma, erythrocyte and brain cholinesterase levels after intraperitoneal injection of 1 to 5 mg/kg of 4-benzothienyl-N-methylcarbamate (MOBAM) were compared with decrements in both spontaneous motor activity and conditioned avoidance performance produced by this compound. Significant effects were observed with all five measured phenomena at dosages producing no obvious clinical signs. In albino rats, a dosage of 2 mg/kg significantly depressed plasma and erythrocyte cholinesterase activity, and decreased motor activity 15 min after injection but only higher dosages (3 and 5 mg/kg) significantly depressed brain cholinesterase activity and avoidance performance. In Long-Evans rats, both brain cholinesterase activity and avoidance performance were significantly reduced by the lower (2 mg/kg) dosage. The avoidance impairments observed after 3 mg/kg could be prevented by prior injection with atropine sulfate. It is suggested that both central and peripheral cholinesterase changes are important in determining the nature of the behavioral effects observed after exposure to this compound.