The role of arginine vasopressin and oxytocin as immunomodulatory hormones on experimental autoimmune encephalomyelitis (876.1)

Abstract

Arginine vasopressin (AVP) and oxytocin (OXT) are pleiotropic hormones released from the neurohypophysis. We demonstrated that neurointermediate pituitary lobectomy (NIL) in rats significantly protects against experimental autoimmune encephalomyelitis (EAE), a demyelinating T cell‐mediated disease of the central nervous system (CNS), whereas administration of desmopressin (DP, an AVP synthetic analog), restores the susceptibility of the NIL animals to EAE. Since immune cells have AVP and OXT receptors, we investigated whether OXT beside AVP, has also an immunomodulatory role on EAE. A comparative study of the effects of NIL, NIL+ DP and NIL+ carbetocin (CBT, a synthetic OXT analog) on clinical symptoms of EAE and on the number of CNS infiltrating lymphocytes were assessed. Animals were immunized for EAE one week after starting the administration of DP and CBT. EAE clinical signs were evaluated daily and CNS lymphocytes were separated with Percoll gradient. In NIL rats DP restored susceptibility to EAE and increased lymphocytic infiltration in the CNS while CBT resulted in very mild EAE symptoms and no changes in CNS lymphocytes. In conclusion, AVP has more powerful immunomodulatory effects than OXT.