Chuang Y C, Fraser M O, Yu Y, Beckel J M, Seki S, Nakanishi Y, Yokoyama H, Chancellor M B, Yoshimura N, de Groat W C
Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
Am J Physiol Regul Integr Comp Physiol. 2001 Oct;281(4):R1302-10. doi: 10.1152/ajpregu.2001.281.4.R1302.
The afferent limb of the vesicovascular reflex (VV-R) evoked by distension or contraction of the urinary bladder (UB) was studied in urethane-anesthetized female rats by examining the changes in VV-R after administration of C-fiber afferent neurotoxins [capsaicin and resiniferatoxin (RTX)]. Systemic arterial blood pressure increased parallel (5.1 to 53.7 mmHg) with graded increases in UB pressure (20 to 80 cm H(2)O) or during UB contractions. The arterial pressor response to UB distension was significantly reduced (60-85%) by acute or chronic (4 days earlier) intravesical administration of RTX (100-1,000 nM) or by capsaicin (125 mg/kg sc) pretreatment (4 days earlier). Chronic neurotoxin treatments also increased the volume threshold (>100%) for eliciting micturition in anesthetized rats but did not change voiding pressure. Acute RTX treatment (10-50 nM) did not alter the arterial pressor response during reflex UB contractions, whereas higher concentrations of RTX (100-1,000 nM) blocked reflex bladder contractions. It is concluded that VV-R is triggered primarily by distension- and contraction-sensitive C-fiber afferents located, respectively, near the luminal surface and deeper in the muscle layers of the bladder.
在乌拉坦麻醉的雌性大鼠中，通过检查给予C纤维传入神经毒素[辣椒素和树脂毒素（RTX）]后膀胱血管反射（VV-R）的变化，研究了膀胱（UB）扩张或收缩诱发的VV-R的传入支。随着UB压力（20至80 cm H₂O）分级增加或在UB收缩期间，全身动脉血压平行升高（5.1至53.7 mmHg）。急性或慢性（提前4天）膀胱内给予RTX（100至1000 nM）或辣椒素（125 mg/kg皮下注射）预处理（提前4天），可使动脉对UB扩张的升压反应显著降低（60-85%）。慢性神经毒素处理还增加了麻醉大鼠诱发排尿的容量阈值（>100%），但未改变排尿压力。急性RTX处理（10至50 nM）在反射性UB收缩期间未改变动脉升压反应，而较高浓度的RTX（100至1000 nM）则阻断反射性膀胱收缩。结论是，VV-R主要由分别位于膀胱腔表面附近和肌层深处的对扩张和收缩敏感的C纤维传入神经触发。
