The effects of carbon disulphide exposure on brain catecholamines in rats

Abstract

1 . Rats exposed to 2.0 mg/l. carbon disulphide (CS₂) in the inspired air for 2 days, 4 h a day, showed a 13% decrease in their brain noradrenaline concentration and a 16% increase in their brain dopamine concentration. 2 . After exposure for 5 or 10 days there was a further decrease in the concentration of noradrenaline in the brain, but brain dopamine returned to the control level. 3 . In animals treated intraperitoneally with 2.0 mg/kg reserpine and exposed 2 and 3 days later to 2.0 mg/1. CS₂ for 4 h per day, the brain dopamine concentration showed a 77% increase compared with the unexposed reserpinized animals, but the noradrenaline concentration remained unchanged. 4 . The dopamine concentrations in the adrenals after 10 days' exposure to 2.0 mg/1. CS₂ were 67% to 100% higher than in the control animals. In reserpinized rats, 2 days' exposure to CS₂ nearly trebled the dopamine content of adrenals. 5 . Exposure to CS₂ had no effect on the tyrosine concentration in the brain, and there was no change in the brain monoamine oxidase (MAO) activity. Tyrosine in the brain showed a 30 to 96% increase in concentration and MAO activity, using kynuramine as substrate, showed an approximately 5 % increase 0.5 to 2 h after the subcutaneous administration of 500 mg/kg sodium diethyldithiocarbamate. 6 . CS₂ at 10⁻²m or lower concentrations had no inhibitory effect on the brain MAO activity in vitro. Diethyldithiocarbamate inhibited MAO at 10⁻²m, but not at 10⁻³m or lower concentrations.