ObjectiveTo investigate the influence of norepinephrine on pulmonary vessel pressure in animal model of septic shock. MethodsTwelve health mongrel dogs were randomly divided into a control group (n=5, intravenously injected with normal saline 1 mL/kg) and an endotoxin group(n=7, intravenously injected with lipopolysaccharide 1 mg/kg). When the systemic blood pressure decreased by more than 40% of baseline before administration, the dogs in two groups were intravenously injected with NE 0.5, 1.0, 2.0, 5.0μg·kg-1·min-1. The interval of each dose was more than 10 minutes. The changes of the pulmonary arterial pressure (PAP), pulmonary venous pressure (PVP), and systemic arterial rressure (SAP) were recorded and compared between two groups. ResultsIn the control group, PAP didn't change significantly after administration (P < 0.05), however, PVP increased obviously after NE administration in dose of 2.0 and 5.0μg·kg-1·min-1 (P < 0.05), and SAP increased obviously after NE administration in dose of 1.0, 2.0 and 5.0μg·kg-1·min-1 (P < 0.01). In the endotoxin group, PAP increased obviously after NE administration in dose of 2.0 and 5.0μg·kg-1·min-1 (P < 0.05), while PVP didn't change significantly (P > 0.05), and SAP increased obviously after NE administration in dose of 1.0, 2.0 and 5.0μg·kg-1·min-1 (P < 0.05). There were significant differences in SAP (P < 0.05), not in PAP and PVP (P > 0.05), between two groups after NE administration at dose of 1.0, 2.0 and 5.0μg·kg-1·min-1. The PVP/SAP and PAP/SAP values didn't change significantly after administration in the control group (P > 0.05). In the endotoxin group, the PVP/SAP and PAP/SAP values increased significantly after LPS administration, and decreased slightly after NE administration in dose of 2.0 and 5.0μg·kg-1·min-1 (P < 0.05). ConclusionsNE administration in septic shock can not increase the angiotasis of the pulmonary vein. NE administration in dose of 2.0 and 5.0μg·kg-1·min-1 can cause the increase of PAP and SAP, but the increase of PAP is lower than the increase of SAP.