The effects of pesticides on monoaminergic system related to periodic activity of mussels ( Anodonta cygnea L.)

Abstract

1. 1. The effect of a herbicide (paraquat) and an insecticide (methidation) on the periodic activity of mussel in relation to serotonin and dopamine levels and their release and uptake in nervous system was investigated. 2. 2. LC 50 values of methidation in 24-, 48-, and 96-hr treatments, respectively, were 50% lower than those of paraquat. 3. 3. Serotonin and dopamine levels decreased in all three ganglia by 20% on average upon 24- and 48-hr in vivo treatments with paraquat. In the 96-hr treatment, however, both monoamines showed a 20–40% increase. With methidation treatment, the level of monoamines tested did not change significantly. 4. 4. After paraquat treatment, both the average lengths of resting periods and their total duration significantly increased. Parallel to this, the average length of active periods and their total duration dramatically decreased. Methidation increased the average length and total duration of resting periods during the first 2 days at the expense of active periods. On the fourth day, however, the effect reversed: average length and total duration of active periods increased of the expense of parameters characteristic of the resting state.