Ogoda Masaki, Ito Yoshihiko, Fuchihata Yusuke, Onoue Satomi, Yamada Shizuo
Department of Pharmacokinetics and Pharmacodynamics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
Center for Pharma-Food Research (CPFR), Graduate School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
J Pharmacol Sci. 2016 May;131(1):58-63. doi: 10.1016/j.jphs.2016.04.020. Epub 2016 Apr 26.
Muscarinic and purinergic (P2X) receptors play critical roles in bladder urothelium under physiological and pathological conditions. Aim of present study was to characterize these receptors in rat bladder urothelium and detrusor muscle using selective radioligands of [N-methyl-(3)H]scopolamine methyl chloride ([(3)H]NMS) and αβ-methylene ATP [2,8-(3)H]tetrasodium salt ([(3)H]αβ-MeATP). Similar binding parameters for each radioligand were observed in urothelium and detrusor muscle. Pretreatment with N-(2-chloroethyl)-4-piperidinyl diphenylacetate (4-DAMP mustard) mustard revealed co-existence of M2 and M3 receptors, with the number of M2 receptors being larger in the urothelium and detrusor muscle. Intravesical administration of imidafenacin and Dpr-P-4 (N → O) (active metabolite of propiverine) displayed significant binding of muscarinic receptors in the urothelium and detrusor muscle. The treatment with cyclophosphamide (CYP) or resiniferatoxin (RTX) resulted in a significant decrease in maximal number of binding sites (Bmax) for [(3)H]NMS and/or [(3)H]αβ-MeATP in the urothelium and detrusor muscle. These results demonstrated that 1) pharmacological characteristics of muscarinic and P2X receptors in rat bladder urothelium were similar to those in the detrusor muscle, 2) that densities of these receptors were significantly altered by pretreatments with CYP and RTX, and 3) that these receptors may be pharmacologically affected by imidafenacin and Dpr-P-4 (N → O) which are excreted in the urine.
毒蕈碱能受体和嘌呤能（P2X）受体在膀胱尿路上皮的生理和病理状况下发挥关键作用。本研究的目的是使用[甲基 - （3）H]氯化东莨菪碱（[（3）H]NMS）和αβ - 亚甲基ATP [2,8 - （3）H]四钠盐（[（3）H]αβ - MeATP）的选择性放射性配体来表征大鼠膀胱尿路上皮和逼尿肌中的这些受体。在尿路上皮和逼尿肌中观察到每种放射性配体具有相似的结合参数。用N - （2 - 氯乙基） - 4 - 哌啶基二苯基乙酸酯（4 - DAMP芥子气）预处理显示M2和M3受体共存，尿路上皮和逼尿肌中M2受体的数量更多。膀胱内给予咪达非那新和Dpr - P - 4（N→O）（丙哌维林的活性代谢物）显示在尿路上皮和逼尿肌中有明显的毒蕈碱能受体结合。用环磷酰胺（CYP）或树脂毒素（RTX）处理导致尿路上皮和逼尿肌中[（3）H]NMS和/或[（3）H]αβ - MeATP的最大结合位点数（Bmax）显著降低。这些结果表明：1）大鼠膀胱尿路上皮中毒蕈碱能受体和P2X受体的药理学特性与逼尿肌中的相似；2）这些受体的密度通过CYP和RTX预处理而显著改变；3）这些受体可能受到尿液中排泄的咪达非那新和Dpr - P - 4（N→O）的药理学影响。
