過伸展膀胱のdenervation supersensitivityについて --過大反応と結合織の変化との関係を中心として--

Abstract

膀胱過伸展のモデルとして雌性雑種成犬の膀胱頸部を糸付きシリコンリングにて結紮し, 48時間の完全尿閉状態を作成した.利尿筋切片のachに対する収縮は尿閉解除後2週群の反応が最大であり, 4週群は無処置群より低い反応を示した.筋層組織像は4週群で筋束への線維増生がみられた.また膀胱血流量を水素ガスクリアランス法を用いて測定し, 48時間尿閉解除直後では膀胱空虚時に比較して63%の血流減少を認めた

To investigate denervation supersensitivity of the detrusor muscle due to prolonged bladder overdistension, overdistended bladders were produced in female mongrel dogs by bladder neck obstruction for 48 hours and the dogs were sacrified 1, 2 and 4 weeks after overdistension. The sensitivity of the detrusor muscle to acetylcholine was measured using the isometric in vitro technique. The bladder wall tissues were examined with Masson's trichrome staining. The blood flow of the bladder wall was determined by the hydrogen gas clearance method. Sensitivity reached a maximum 2 weeks after overdistension, thereafter decreasing to a lower level 4 weeks after overdistension than that of the untreated detrusor muscle. A decrease of blood supply to the bladder wall, the rate being 63% immediately after overdistension, may result in a degeneration of the axon which is more fragile to ischemic changes. Subsequently axonal degeneration may be followed by denervation supersensitivity of the detrusor muscle. Remarkable fibrotic changes of the bladder wall 4 weeks after overdistension suggested a decrease of the detrusor muscle contraction to acetylcholine.