Histofluorescence study and biochemical assay of catecholamines (dopamine and noradrenaline) during the course of arm-tip regeneration in the starfish, Asterina gibbosa (Echinodermata, Asteroidea).

In the starfish, Asterina gibbosa, the histofluorescence method gives evidence of an aminergic activity in the course of arm-tip regeneration. This activity can be detected as variations in the localization and intensity of a green fluorescence in the nerve structures of the arm, the radial nerve, and the circumoral nerve ring connected to it. Biochemical assays reveal that dopamine levels increase on the 2nd and 4th days of regeneration, when the blastema is forming and when differentiation commences. The level of noradrenaline also increases on the 2nd day after amputation of the arm.