Seasonal characteristics of the monoaminergic regulation of the behavior of hibernating animals

The stimulating effect of L-DOPA on exploratory activity of the ground squirrel in the hole-board and open field experiments was stronger in the spring than in autumn, whereas the regulating effect of the 5-HTP on adaptive behaviour of hibernating animals was stronger in autumn. Results of the biochemical analysis of the MAO A activity with serotonin or noradrenaline as substrates revealed a seasonal dependence of the substrate specific changes of this enzyme activity in hibernating animals. The data obtained suggest that the seasonal distinctions in effects of similar pharmacological agents depend on activity of the brain monoaminergic systems' activity in hibernating animals in different periods of the annual cycle.