ALPHA-2-ADRENOCEPTORS IN HOMOGENATES OF RAT NASAL-MUCOSA

The specific binding of [3H]rauwolscine to rat nasal mucosa membranes was saturable, stereoselective and of high affinity. The Scatchard plot pointed to a homogeneous population of binding sites (Kd = 3.6 ± 0.6 nM; Bmax = 5.1 ± 0.7 pmol/g). The non-specific binding appeared to be non-linear, probably due to filter binding. Inhibition of [3H]rauwolscine binding with the subtype-selective antagonist, prazosin, suggested the presence of α2-adrenoceptor subclasses in rat nasal mucosa. The (-)-epinephrine inhibition curves demonstrated high- and low-affinity agonist binding sites. A monophasic (-)-epinephrine inhibition curve was obtained in the presence of guanine nucleotides. © 1990.