Hypothalamic endocannabinoid system participates in the increase in plasma oxytocin and TNF-alpha levels during infection

DE LAURENTIIS, ANDREA; FERNÁNDEZ-SOLARI, JAVIER; PRESTIFILIPPO, JUAN PABLO; MOHN, CLAUDIA; ZORRILLA ZUBILETE, MARÍA A; RETTORI. VALERIA

Buenos Aires 20-23 de Abril

Congreso; III Iberoamerican Congreso of Neuroimmunomodulation; 2009

During infection plasma TNF-a levels are increased. Also, changes in oxytocin (OT) secretion were described. OT is synthesized in neurons of hypothalamic PVN and SON nuclei and most of its fibers terminate in neurohypophysis (NH) from where secreted OT reaches systemic circulation. Endocannabinoids (ECs) have significant effects on neuroendocrine function and hormone secretion. Since ECs and its receptors are present in cells of the hypothalamic PVN and SON nuclei, it is possible that ECs modulate OT secretion. In the present work we studied the participation of the EC system on the effect of lipopolysaccharide (LPS) on TNF-a and OT plasma levels in adult male rat. LPS injected (ip, 5mg/kg, 1hr) increased highly significantly both OT (RIA) and TNF-a (ELISA) plasma levels. These stimulatory effects were partially reversed when together with LPS injection, a CB1 receptors antagonist was administered into third hypothalamic ventricle (icv) (AM251, icv, 500ng/5ml) and also when a CB2 receptors antagonist (AM630, icv, 500ng/5ml) was coadministered with AM251. Our results show that hypothalamic EC system participates in the increase in plasma OT and TNF-a levels during infection. Grants: CONICET PIP 6149, ANPCyT PICT 06-00258.