Effects of estivation on the levels of biogenic amines and related compounds in the ganglia, the auricle, and the ventricle of the heart of the pulmonate land snail Helix lucorum (L): evidence for physiological roles of serotonin and dopamine in thec

摘要

The contents of biogenic amines and related compounds were measured by HPLC with electrochemical detection (HPLC-ED) in extracts of ganglia, auricle and heart ventricle of H. lucorum. Measurements were taken after 15 and 20 days, and 1, 2 and 3 months of aestivation. The chromatograms obtained from ganglia samples from active and aestivating H. lucorum revealed the presence of dopamine (DA) and serotonin (5-HT). In addition, small peaks corresponded to analytes with retention time similar to that of 5-HTP [5-hydroxytryptophan], an immediate precursor of 5-HT, and to that of 3,4-dihydroxy phenylacetic acid (DOPAC), a metabolite of DA, were also observed. On the contrary, 5HIAA [5-hydroxyindoleacetic acid], a metabolite of 5-HT, was observed only inchromatograms obtained from ganglia samples of aestivating snails. DA and 5-HT were the only biogenic amines that were always detectable in the auricle and the ventricle of both active and aestivating snails. Over the course of aestivation, significantfluctuations in the content of DOPAC were observed in the ganglia. Significant fluctuations of 5-HT content were also observed in the ventricles and the auricles during aestivation, whereas the most remarkable changes in DA content were observed in the ventricles. The periodic changes in the content of DOPAC and of 5HIAA in the ganglia, and the fluctuations of the DA and 5-HT contents in the heart indicate that heart activity is modulated periodically by serotonergic and dopaminergic fibres in H. lucorum during aestivation.