Role of propofol in peripheral lymphocytic β1 adrenergic receptor desensitization in elderly patients

AIM: To evaluate the role of propofol in peripheral lymphocytic β1 adrenergic receptor (AR) desensitization in elderly patients. METHODS: Thirty elderly patients were recruited into the study and were classified into three groups (n=10): low-dose group (L) with propofol (1.0 mg/kg), high-dose group (H) with propofol (2.0 mg/kg) and control group (C). Lymphocytes were isolated and expressions of β1-AR in cytoplasm and cytomembrane were detected with Western blot. Isoproterenol-stimulated cAMP products in lymphocytes were measured with radioimmunoassay. Before and after injection, blood pressure (BP) and heart rate (HR) were also recorded. RESULTS: Systolic blood pressure (SBP), diastolic blood pressure (DBP), cAMP product and β1-AR level in lymphocytic cytomembrane in the L group and H group were all lower than in the control group (P<0.05 or P<0.01). On the contrary, β1-AR protein level in lymphocytic cytomembrane in the L group and H group was significantly more abundant than in the control group (P<0.05 or P<0.01). CONCLUSION: Clinically relevant concentrations of propofol attenuate -adrenergic signal transduction in peripheral lymphocytes via promotion to the internalization of β1-AR and inhibition of cAMP production, which may be a contributory factor in cardiac vascular inhibition.