the cardiovascular responses after lipopolysaccharide microinjection into the dorsomedial periaqueductal gray in rats

Introduction: the dorsomedial periaqueductal gray (dmpag) is located around the cerebral aqueduct with various functions such as cardiovascular regulation and is affected by inflammation. lipopolysaccharide (lps) is a complex molecule with an inflammatory effect that is known to affect blood pressure. in the present study, the cardiovascular effect of lps microinjection into the dmpag was investigated. methods: rats were divided into three groups consisting of 1: control; 2: 50 ng lps and 3: 100 ng lps. rats were mounted on a stereotaxic device after anesthesia and a continuous recording of cardiovascular parameters was done by a powerlab device, connected to a cannulated femoral artery and drugs microinjected into dmpag. the changes (∆) in systolic blood pressure (sbp), diastolic blood pressure (dbp), mean arterial pressure (map) and heart rate (hr) were calculated at different times and compared to the control group. results: both doses of lps when microinjected into the dmpag brought on a significant hypotensive response in the pressure parameters (map, sbp, and dbp) when compared to control. a non-significant increase in hr was also documented in both groups. conclusion: the results of this experiment indicated that lps, when microinjected into the dmpag, induced a hypotensive response in anesthetized rats in both doses in comparison to control.