Objective:To investigate the effects of central and peripheral injection of arginine vasopressin (AVP) on arterial baroreflex (ABR) function in septic rats.
Methods:Rat sepsis model  was induced by cecal ligation and puncture (CLP).  (1) The ABR function and AVP expressions in supraoptic and paraventricular nucleus of the 2 grous were measured at 4, 8 and 12 h after operation, respectively. The sham operated rats were used as control;  (2) Sepsis rats were given AVP (50 ng), and artificial cerebrospinal fluid of the same volume were given to control rats by intracerebroventricular injection 8 h after operation. The ABR functions of the 2 group rats were determined at 5 and 30 min after injection. (3)Sepsis rats were given AVP ［2 ng/(kg·h)］ and control rats were given saline of the same volume by continuous intravenous infusion 6 h after CLP. The ABR functions of the 2 group rats were determined at 5 and 30 min after infusion. 
Results:In sepsis rats showed gradual decrease in ABR function, as well as a gradual reduction of AVP expressions in supraoptic and paraventricular nucleus. Both intracerebroventricular injection and continuous intravenous infusion with AVP significantly improved the ABR functions in sepsis rats compared with control group rats (both P<0.05).
Conclusions:In sepsis, the reduction of AVP expression in supraoptic and paraventricular nucleus induces a decrease in ABR function, which may probably contribute to the development of sepsis. Use of exogenous AVP in the initial phase of sepsis can improve ABR function and delay the development of sepsis.