Cytochemical and biochemical characterization of neurosecretory material in the brain of an annelid, Ophryotrocha puerilis (Polychaeta).

In the brain of the protandric annelid Ophryotrocha, prominent axon terminals accumulate neurosecretory material in female-phase individuals. This material is not present in females after they have had social contact for 2 days and in males. After treatment with Formalin or glyoxylic acid, the axon terminals in isolated females are brightly fluorescent. The injection of reserpine into the coelomic cavity of such females prevents the development of fluorescence in the nerve endings. In an HPLC study of brains containing axon terminals filled with neurosecretory material, catecholamines were found to be present in large quantities. In specimens with empty axon terminals, the amount of catecholamines was significantly less. Thus the secretory material appears to contain catecholamines. The results presented suggest dopamine to be the major component of the neurosecretory material.