title: Characterization of muscarinic receptors in the human bladder mucosa: direct quantification of subtypes using 4-DAMP mustard.
abstract: OBJECTIVE
  To characterize pharmacologically relevant muscarinic receptors in the human bladder mucosa and detrusor muscle using radioligand binding assays with [N-methyl-3H]scopolamine methyl chloride ([3H]NMS) and 4-DAMP mustard.
  
  
  METHODS
  Muscarinic receptors in homogenates of bladder mucosa, detrusor muscle, and parotid gland were measured using the radioligand [3H]NMS. 4-DAMP mustard was used to inactivate M3 receptors irreversibly.
  
  
  RESULTS
  Specific [3H]NMS binding in the homogenates of the mucosa and detrusor muscle was saturable and of high affinity as shown by dissociation constants (Kd) of 260 ±82 and 237 ±49 pM, respectively. Antimuscarinic agents (oxybutynin, propiverine, tolterodine, and darifenacin) and their active metabolites competed with [3H]NMS for the binding sites in the human mucosa in a concentration-dependent manner. These agents exhibited similar affinity in the detrusor muscle. The Bmax. values of [3H]NMS in the detrusor, bladder mucosa, and parotid gland were significantly decreased by pretreatment with 4-DAMP mustard (36%, 41% and 63%, respectively).
  
  
  CONCLUSIONS
  The density and binding affinity profile of the muscarinic receptor population in the human bladder mucosa was shown to be similar to that of the detrusor muscle. The density of the M3 subtype in the mucosa was similar to that in the detrusor muscle but lower than that in the parotid gland.
authors.affiliation: Department of Pharmacokinetics and Pharmacodynamics and Global Center of Excellence Program, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yoshida
authors.forename: Masanao
authors.initials: M
authors.lastname: Seki
authors.forename: Sweety
authors.initials: S
authors.lastname: Nasrin
authors.forename: Atsushi
authors.initials: A
authors.lastname: Otsuka
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Ozono
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takeda
authors.forename: Keisuke
authors.initials: K
authors.lastname: Masuyama
authors.forename: Isao
authors.initials: I
authors.lastname: Araki
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Ehlert
authors.forename: Shizuo
authors.initials: S
authors.lastname: Yamada
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001667:Binding, Competitive; D004158:Diphenylacetic Acids / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000378:metabolism; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009130:Muscle, Smooth / Q000378:metabolism; D019832:N-Methylscopolamine / Q000494:pharmacology; D010306:Parotid Gland / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology*; D011869:Radioligand Assay; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D001743:Urinary Bladder / Q000378:metabolism*
chemical_list: D004158:Diphenylacetic Acids; D018727:Muscarinic Antagonists; D010880:Piperidines; D011976:Receptors, Muscarinic; C074183:N-(2-chloroethyl)-4-piperidinyl diphenylacetate; D019832:N-Methylscopolamine