Presence of and stress-related changes in urocortin-like molecules in neurons and immune cells from the mussel Mytilus galloprovincialis

The distribution of urocortin (UCN)-like material is investigated in the bivalve molluscMytilus galloprovincialis. Immunocytochemical data demonstrate that UCN-like moleculesare present in ganglionic neurons, microglial cells and immunocytes. Moreover, a colocalizationof UCN- and corticotrophin-releasing hormone (CRH)-like molecules is foundin microglial cells and in immunocytes, but not in neurons. Following high salinity-stress experiments, immunoreactivity for UCN and CRH increased in ganglionic neurons and immunocytes. Our findings extend the number of molecules potentially used by molluscan immunocytes to confront stress situations and strengthen the idea of functional conservation of stress-related molecules during evolution.