β-Adrenoceptors and Adenylcyclase Activity in Erythrocytes from Rats Pretreated with Isoprenaline

Specific desensitization of adrenergic receptors has been reported by several investigators (c.f. Wolfe et al. Ann.Pharmacol.Toxicol. 17, 575, 1977). It has been, therefore, investigated, whether adrenergic β-receptors in immature red blood cells from rats (after pretreatment with acetylphenylhydrazine 3 × 40 mg/kg) could be desensitized by treatment of the animals with high doses of (±) isoprenaline (Ipn; 4 × 30 mg/kg within 24 hours before decapitation). cAMP synthesis was measured in suspensions of intact cells or in membrane preparations; receptor density was determined using 3H (−)-dihydroalprenolol (DHAP).