Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Neurourol Urodyn. 2011 Jan;30(1):144-50. doi: 10.1002/nau.20965.
To investigate the distribution of beta-3 adrenergic receptors (β(3)ARs) in the rat bladder and to examine the contribution of urothelial β(3)ARs to agonist-induced suppression of bladder reflexes and relaxation of smooth muscle.
Bladder tissue was collected from 8- to 10-month old female SD rats. In some samples, the urothelium was surgically separated from the smooth muscle. The expression and localization of βAR mRNA and β(3)AR protein were determined using RT-PCR and immunohistochemistry. Contractile responses to the specific β(3)AR agonists TAK-677 and BRL37344 were measured in bladder strips with or without the urothelium. The contribution of urothelial β(3)ARs to the micturition reflex was assessed in continuous cystometry in urethane anesthetized rats using intravesical delivery of β(3)AR agonists.
RT-PCR detected mRNA of all βARs in urothelium and smooth muscle. Immunostaining detected β(3)ARs throughout the urothelium, in the smooth muscle, myofibroblast-like cells, and in the peripheral nerves. Ovariectomy did not change the distribution of β(3)ARs in any bladder structure. Intravesical administration of TAK-677 and BRL37344 (1-5 × 10(-4) M) decreased voiding frequency and amplitude of bladder contractions. In bladder strips in vitro both β(3)AR agonists (10(-12) to 10(-4) M) relaxed the smooth muscle in a concentration-dependent manner to the same extent in strips with and without the urothelium.
In addition to their presence in bladder smooth muscle, β(3)ARs are present in the urothelium where their activation may alter reflex voiding via release of factor(s) that act on non-myocyte structures including the afferent and/or efferent nerves to influence bladder contractility.
研究大鼠膀胱中β-3 肾上腺素能受体（β(3)ARs）的分布，并探讨尿路上皮β(3)ARs 对激动剂诱导的膀胱反射抑制和平滑肌松弛的贡献。
从 8-10 月龄雌性 SD 大鼠中收集膀胱组织。在一些样本中，通过手术将尿路上皮与平滑肌分离。使用 RT-PCR 和免疫组织化学测定 βAR mRNA 和 β(3)AR 蛋白的表达和定位。在有或没有尿路上皮的膀胱条带中测量特异性 β(3)AR 激动剂 TAK-677 和 BRL37344 的收缩反应。在乌拉坦麻醉的大鼠连续膀胱测压中，通过膀胱内给予 β(3)AR 激动剂评估尿路上皮 β(3)ARs 对排尿反射的贡献。
RT-PCR 在尿路上皮和平滑肌中检测到所有 βARs 的 mRNA。免疫染色检测到 β(3)ARs 存在于整个尿路上皮、平滑肌、肌纤维母细胞样细胞和周围神经中。卵巢切除术未改变任何膀胱结构中 β(3)AR 的分布。膀胱内给予 TAK-677 和 BRL37344（1-5×10(-4)M）可降低膀胱收缩的排尿频率和幅度。在离体膀胱条带中，两种 β(3)AR 激动剂（10(-12) 至 10(-4)M）以浓度依赖的方式以相同的程度松弛平滑肌，无论是否有尿路上皮。
除了存在于膀胱平滑肌中，β(3)ARs 还存在于尿路上皮中，其激活可能通过释放作用于非肌细胞结构（包括传入和/或传出神经）的因子来改变反射性排尿，从而影响膀胱收缩性。
