Age-related Changes Of Peripheral Benzodiazepine Receptors In Synaptosoms In Spinal Cord And In Platelet Membrane In Rats

Objective To investigate correlations between peripheral-type benzodiazepine receptors(PBRs) in synaptosomes in the spinal cord and in platelet membrane in rats during ageing and to explore the significance of the relationships.Methods Sprague-Dawley rats of both sexes were divided into 3- and 24-month groups.All animals were sacrificed by decapitation and the spinal cords were immediately removed.Synaptosomal fractions from spinal cord were isolated by gradient centrifugation.The membrane of platelets from venous blood was prepared by the method of hypotonic haemolysis.The specific binding assay of the radioactive PBR antagonist[~3H]PK11195 to membrane was performed.Results A significant difference about[~3H]PK11195 binding activity of synaptosomes of spinal cord was observed among two groups and for platelet membrane.An age-related decrease was found for the two indexes above.A positive relationship about[~3H]PK11195 binding activity) was found between platelet membrane and spinal cord synaptosomes(r=0.985,P＜0.001).Conclusions The levels of PBRs decreased in synaptosomes of spinal cord with ageing.[~3H]PK11195 binding activity of platelet membrane might reflect the changes of PBRs in the spinal cord.