Effects Of Different ?-Adrenergic Receptors On Hemodynamics In Hypoxia Rats

Objective:To explore the effects of different ?-adrenergic receptors??-AR?on hemodynamics in hypoxia anesthetized rats.Methods : Rats were randomly divided into Control group,?1-ARblocker group?Atenolol group?,?2-ARblockergroup?ICI 118,551 group?and nonselective?-AR blocker group?Propranolol group?,after 10 min of treatment were experimented in normoxia?oxygen content of 20.9%?and hypoxia?oxygen content of 15%?.Monitored the changes of central venous pressure?CVP?,the mean arterial pressure?MAP?,the pulmonary artery pressure?PAP?,the maximum rate of right ventricular pressure?± dP/dtmax?,the left arterial pressure?LAP?,the ascending aorta blood flow?ABF?,the heart rate?HR?,the airway pressure?Paw?,the pulmonary vascular resistance?PVR?,the total peripheral resistance?TPR?,and compared the arterial blood gas analysis of normoxia and hypoxia 5min.Results: In normoxia?20.9% O₂?,the ABF,HR,MAP,PAP and ±dP/dtmaxof right ventricular of Propranolol and Atenolol group were decreased?P<0.05?,and the changes have significant difference compared with Control group?P<0.05?.In hypoxia?15% O₂?,the PVR was increased and TPR was decreased of Propranolol and ICI 118,551 group?P<0.05?,the ±dP/dtmaxof right ventricular were increased of Control,Propranolol and Atenolol group?P<0.05?,and the changes of Propranolol and Atenolol group have significant difference compared with Control group?P<0.05?.Conclusions: Inacute hypoxic stress response process,the sympathetic-adrenal medulla system through activation of ?-AR to play its effect on the pulmonary circulation.The regulation of pulmonary vascular tone mainly through activation ?2-AR,and its acting can inhibit the hypoxia pulmonary arterial pressure increased in a certain extent.In addition,acute hypoxia may cause a compensatory increase of the capacity in the right ventricular diastolic and diastolic.