Affinity Labeling of Adenosine A₁ Binding Sites

Abstract: The adenosine A₁ receptors of sheep brain membranes have been identified by the specific binding of radio-labeled cyclohexyl [³H]adenosine ([³H]CHA). Pretreatment of membranes with periodate-oxidized CHA causes a doseand time-dependent decrease in the number of binding sites. No decrease occurs when membranes are pretreated with CHA. Binding of [³H]CHA to the remaining sites occurs with the same characteristics as binding to the untreated receptor population.