[Comparison of muscarinic cholinoceptor densities and affinities in the normal, obstructed and denervated human detrusor].

: Muscarinic cholinoceptor densities and dissociation constants in normal, obstructed and denervated human detrusors were determined using 3H-quinuclidinyl benzilate (3H-QNB) as a radioligand in binding assays. Samples of detrusor were taken from 22 normal bladder domes (bladder tumor 10, primary VUR 5 and others 7), from normal bladder base in 10 bladder tumor cases, from obstructed bladders in 12 cases of benign prostatic hypertrophy and from denervated bladders in 6 spina bifida patients. The binding assay for muscarinic cholinoceptor was performed according to the procedures of Yamamura et al. and Nilvebrant et al. The tissue samples were homogenized in ice cold phosphate buffer (0.05 M, pH 7.4) by a Polytron homogenizer and the homogenates were used immediately for the receptor binding assay. Homogenates (100 microliters) in the presence or absence of 10 microM atropine sulfate and various concentrations (0.05-3 nM) of 3H-QNB, diluted with phosphate buffer to 2 ml were incubated for 90 minutes at 25 degrees C. The solutions were filtered through Whatman GF/F glass fiber filters. The filter was placed in a scintillation vial with 10 ml of scintillation fluid (ACS-II) for 24 hours. The radioactivity was determined by liquid scintillation spectrometry. The maximum binding (B max) and dissociation constant (KD) were derived by Scatchard analysis. B max is expressed as f mol/mg protein, and KD as M.(ABSTRACT TRUNCATED AT 250 WORDS)