Role of baroreflex during endotoxemic shock

Septic shock is a prevalent and life‐threatening condition which is often associated with major hypotension, resulting in multiple organs failure. The infusion of high doses of endotoxin lipopolysaccharide (LPS) is a well‐accepted experimental model of septic shock. Considering that baroreflex is a mandatory mechanism involved in the beat‐to‐beat hemodynamic regulation, we hypothesized herein that baroreflex plays a role buffering endotoxin‐induced hypothension in conscious freely moving rats. Thus, in the present study, we evaluated the cardiovascular outcomes of iv injection of endotoxin (1.5 mg.kg−1 or 2.5 mg.kg−1) or saline in male Wistar rats (280–350g, CEUA #2017.1.585.58.9). The baseline levels of mean arterial pressure and heart rate were not different among all groups. As expected, endotoxin induced hypotension (P<0.001) and tachycardia (P < 0.001). These effects were independent of dose. Interestingly, the drop of mean arterial pressure was significantly higher in rats previously submitted to baroreceptors afferents removal (4 days before recordings) than in (sham) rats with intact baroreceptor afferents (P<0.001). The present data are consistent with the notion that baroreflex is key lessening endotoxin‐induced hypothension. The neural mechanisms involved in this control deserve further investigation aiming new strategic therapeutic tools to revert this critical condition.Support or Funding InformationFinancial support: FAPESP, CAPES and CNPqThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.