A role for CXC chemokines and their receptors in stress axis regulation of common carp

Although chemokines mainly function to activate leukocytes and to direct their migration, novel evidence indicates non-immune functions for chemokines within the nervous and endocrine systems. These include development of the nervous system, neuromodulation, neuroendocrine regulation and direct neurotransmitter-like actions. In order to clarify a potential role for chemokines and their receptors in the stress response of fish, we studied changes in the expression patterns of CXC ligands and their receptors in the stress axis organs of carp, during a restraint stress procedure. We showed that stress down-regulated the gene expression of CXCL9-11 (CXCb1 and CXCb2) in stress axis organs and up-regulated expression of CXCR4 chemokine receptor in NPO and pituitary. Moreover, upon stress, reduced gene expression of CXCL12a and CXCL14 was observed in the head kidney. Our results imply that in teleost fish, CXC chemokines and their receptors are involved in neuroendocrine regulation. The active regulation of their expression in stress axis organs during periods of restraint indicates a significant role in the stress response.