Monoamine level and periodic activity in 6-hydroxydopamine treated mussels Anodonta cygnea L

In the central nervous system of the mussel (Anodonta cygnea) 6-hydroxydopamine (6-OHDA) causes a significant and prolonged decrease in the dopamine (DA) and noradrenaline (NA) concentration. The decrease of serotonin (5HT) level did not exceed 25 per cent and was observed only on the 2nd and 3rd day after the treatment. Parallel with the alteration of the monoamine level, there is a marked change in the activity of the animals. Two phases of the effect of 6-OHDA can be distinguished. During the first phase, not only the catecholaminergic but, presumably, also the serotoninergic system is injured. The long-lasting effect of the 6-OHDA administration is reflected in the predominance of the active periods and in the absence of rest periods of the animal.