Quantitative analysis of alpha and beta adrenergic receptor densities in the lower urinary tract of the dog and the rabbit.

Using specific radioligand receptor binding assays, we have, for the first time, quantitated both alpha- and beta-adrenergic receptors in the musculature of the lower ureter, bladder body, posterior bladder base, and proximal urethra of the dog, and in the bladder base and body of the rabbit. For the beta receptor assay 3H-dihydroalprenolol was used as the ligand, and, for the alpha receptor assay, 3H-dihydroergocryptine was used. In the dog, there was a significantly greater density of beta receptors in the bladder body than in either the ureter or the posterior bladder base. The urethra had an intermediate density. The bladder base and the proximal urethra had a significantly greater density of alpha receptors than either the ureter or the bladder dome. The dissociation constant of beta receptors for DHA was approximately 9 nM for all tissues studied, and that of alpha receptors for DHE approximately 7 nM. A similar distribution of alpha-and beta adrenergic receptors was seen in the rabbit bladder.