ヒト膀胱平滑筋のムスカリン性アセチルコリン受容体の定量および正常,閉塞性,除神経膀胱における受容体量の比較

Abstract

3H-quinuclidinyl benzilateを使用してreceptor binding assayを行い, ヒト膀胱平滑筋のムスカリン性アセチルコリン受容体量(Bmax)と解離定数(KD)を測定した.1)対象は正常膀胱22例, 前立腺肥大症に伴う閉塞性膀胱12例, 2分脊椎症に伴う除神経膀胱6例の計40症例である.2)正常膀胱体部においてはBmax, KDの値に関して性差, 年齢差は認められず, 全体としてBmax=43.1±12.3 fmol/mg・protien, KD=(1.12±0.67)×10-10 Mであった.3)正常膀胱三角部ではBmax=23.8±7.0 fmol/mg・protein, KD=(1.45±0.64)×10-10 Mであり, 三角部でのBmaxは体部に比較して有意に低かった.4)前立腺肥大症に伴う閉塞性膀胱体部ではBmax=39.9±11.5 fmol/mg・protein, KD=(1.04±0.35)×10-10 Mであり, 2分脊椎症に伴う除神経膀胱体部ではBmax=48.4±12.1 fmol/mg・protein, KD=(1.63±0.5)×10-10 Mであった.正常群に対して前立腺肥大症群のBmaxは低値, 2分脊椎症群のそれは高値を示し, これは動物実験で示された傾向と一致するが, 有意差は認められなかった.KDについても同様に有意差はなかった.5)正常膀胱体部の小児例8例, 前立腺肥大症に伴う閉塞性膀胱体部12例においてstable bladderとunstable bladderとの比較をしたが, Bmax, KDともに有意差を認めなかった

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)