The alpha-adrenoceptor subtype mediating the tension of human prostatic smooth muscle

We have characterized the α₁ adrenoceptor subtypes in the human prostate using radioligand receptor binding studies. The objective of the present study was to determine the α₁ subtype mediating the tension of prostatic smooth muscle. Fresh human tissue was obtained from 9 males between 50 and 80 years of age undergoing prostatectomy for BPH. The incubation of prostatic tissue with the irreversible antagonist chlorethyclonidine (CEC) resulted in an 80% reduction of the maximal contractile response produced by phenylephrine. However, the α_1A-selective antagonists WB-4101 and 5-methylurapidil (5-MU) competitively inhibited the contractile response induced by phenylephrine, with K_B = 2.64 and 4.46 nM, respectively, consistent with their affinity at the α_A1 receptor subtype. The pharmacological profile of the α₁-receptor-mediated contractile response of prostate smooth muscle is inconsistent with their classification as either an α_1A or α_1B subtype. Alternatively, when compared with the properties of the cloned α₁ receptors, our results suggest that the α₁ receptors involved in the contraction of prostate smooth muscle have some pharmacological properties similar to those encoded by the gene of the bovine α_1c receptor subtype. The findings of the present study suggest that efforts should be made to confirm the identity of the α₁-receptor subtype expressed by prostate smooth muscle, in order to develop subtype-selective α₁ antagonists, and to evaluate their safety and efficacy in benign prostatic hyperplasia (BPH). © 1993 Wiiey-Liss, inc.     

异丙酚对离体人支气管平滑肌的作用

目的 观察异丙酚对离体人肺叶支气管平滑肌的作用。方法 离体人肺叶支气管取自胸外科肺叶切除术患者（n=10）,采用离体气管实验法,以乙酰胆碱（3μg·ml-1）激发,观察临床相关剂量的异丙酚（1、2、5、10、20μg·ml-1）对离体人肺叶支气管平滑肌的作用,脂肪乳剂作为对照。结果与对照组相比,1、2、5、10、20μg·ml-1的异丙酚显著减弱乙酰胆碱的平滑肌收缩反应（P值分别<0.05、<0.01、<0.01、<0.01、<0.01）。结论 临床相关剂量的异丙酚可有效地减弱乙酰胆碱介导的离体人肺叶支气管平滑肌的收缩反应.     

Potassium channels and human corporeal smooth muscle cell tone: further evidence of the physiological relevance of the Maxi-K channel subtype to the regulation of human corporeal smooth muscle tone in vitro

PURPOSE: Recent evidence indicates that the large conductance, voltage dependent, Ca2+ sensitive K channel or Maxi-K has an important role in the modulation of human corporeal smooth muscle tone and, thus, in erectile capacity. We further clarified the contribution of the Maxi-K channel subtype to the generation of contractile responses in isolated human corporeal tissue strips. MATERIALS AND METHODS: We performed pharmacological studies of phenylephrine contracted isolated corporeal tissue strips in the presence and absence of the 2 Maxi-K channel blockers tetraethylammonium chloride (TEA) and charybdotoxin, and the Maxi-K opener NS1619. K channel treatment effects were evaluated using 2 parameters, including 1) the steady state parameter of the empirically determined peak magnitude of the steady state contractile response and 2) the kinetic parameter of time required to achieve half of the peak steady state contractile response or half-time. Electrophysiological studies in freshly isolated and cultured myocytes were performed in parallel to corroborate findings further at the tissue level. RESULTS: Pre-incubating isolated human corporeal tissue strips with 1 mM. TEA and 1 microM. charybdotoxin was associated with an approximate 20% increase in the peak steady state contractile response and a corresponding approximate 20% decrease in the half-time of the phenylephrine induced contractile response. Conversely, pre-incubation with 10 microM. NS1619 produced a significant, approximately 20% decrease in the peak steady state contractile response and an approximate 38% increase in the half-time of the phenylephrine induced contractile response. Adding 30 to 180 microM. NS1619 to phenylephrine pre-contracted smooth muscle strips resulted in a 30% to 50% reduction in steady state contractile tension. No detectable effect of NS1619 was observed in 120 mM. KCl or 100 mM. TEA pre-contracted corporeal tissue strips. Whole cell recordings of freshly isolated and cultured corporeal myocytes confirmed that 30 microM. NS1619 induced a charybdotoxin sensitive hyperpolarizing current mediated by the Maxi-K channel. CONCLUSIONS: These in vitro studies confirm and extend previous observations indicating the importance of the Maxi-K channel for regulating human corporeal smooth muscle tone, and by extension, erectile capacity and function.     

人阴茎海绵体平滑肌细胞的原代培养及鉴定

目的　为研究人阴茎勃起功能提供方便的实验材料。　方法　取新鲜尸体阴茎海绵体平滑肌细胞 ,用含 2 0 %人AB型血清的DMEM液作体外原代培养 ,并以免疫组化法鉴定。　结果　经 10～ 14d培养后 ,6个培养瓶内均铺满梭状细胞 ,免疫组化法鉴定确认为人阴茎海绵体平滑肌细胞。　结论　人阴茎海绵体平滑肌细胞可在体外条件下生长传代 ,并可能成系 ,为阴茎勃起功能的研究提供方便的材料     

Microarray analysis of exstrophic human bladder smooth muscle

OBJECTIVE

To compare the genetic profiles of ‘healthy’ bladder smooth muscle cells (SMCs) and exstrophic SMCs (ESMCs) to identify genes that are over‐ and under‐expressed in ESMCs, thus providing a molecular evaluation of the quality and therapeutic potential of ESMC tissue.

PATIENTS, MATERIAL AND METHODS

Classical bladder exstrophy is a rare disorder, occurring in 1 in 30 000 live births. Studies have shown that exstrophic bladders are developmentally immature at birth. After surgical closure, the bladder typically undergoes abnormal remodelling (such as over‐expression of collagen III) throughout early development. We hypothesized that the predominant genetic differences between normal SMCs and ESMCs are in the developmental genes. This hypothesis was tested by the use of microarray analysis. Bladder SM biopsies were taken from ‘healthy’ subjects undergoing bladder surgeries for other conditions (for example, urinary reflux) and patients with bladder exstrophy. Cells were expanded in vitro, and total RNA was isolated and hybridized to the Affymetrix U133A GeneChip® (Affymetrix Inc., Santa Clara, CA, USA) by the Wake Forest University School of Medicine Affymetrix core facility, using standard protocols.

RESULTS

We created a genetic signature consisting of 961 genes that are over‐expressed and 432 genes that are under‐expressed in ESMCs. Analysis of these signatures identified an over‐expression of inflammatory genes and an under‐expression of developmental genes.

CONCLUSION

Our data is in concordance with previous studies and histological data showing that ESMCs are developmentally immature relative to healthy bladder SM. The clinical implication of the ESMC genetic signature is that it provides a list of targets that can be (i) manipulated ex vivo and/or in vivo to induce differentiation (the completion of development) and (ii) used as biomarkers to explain the variability of the clinical symptoms after surgical closure.     

人类脑动脉瘤血管平滑肌细胞表型蛋白与雌激素受体表达

目的 探讨正常人体动脉血管和脑动脉瘤的血管平滑肌(VSMC)雌激素受体(ERs)和α-平滑肌肌动蛋白(α-SMA)和结蛋白(Desmin)表达变化的关系.方法 临床取材8例非动脉瘤患者手术区头部动脉血管和脑动脉瘤切除标本18例.采用免疫组织化学和形态学分析方法 检测正常动脉血管和脑动脉瘤ERs、α-SMA和Desmin的表达.结果 脑动脉瘤VSMC的ERα和ERβ表达水平均高于对照动脉血管表达水平,差异有统计学意义(P<0.01).脑动脉瘤VSMC的α-SMA和Desmin的表达水平均低于对照动脉血管表达水平,差异有统计学意义(P<0.01).脑动脉瘤VSMCERs的表达与α-SMA和Desmin的表达水平明显相关.结论 人类脑动脉瘤VSMC的ERs表达水平普遍升高,其VSMC表型蛋白表达水平普遍降低,两者之间呈负相关,这可能与脑动脉瘤的形成有关.     

改良组织块法成人主动脉血管平滑肌细胞的培养

目的 建立成人主动脉血管平滑肌细胞体外培养的有效方法.方法 无菌条件下分离成人主动脉的平滑肌层,剪成1 mm3的碎片,0.1％ Ⅰ型胶原酶预处理1h,组织块贴壁法,以含胎牛血清20％的DMEM低糖培养基培养.倒置显微镜观察培养细胞的形态学特点,免疫荧光法检测平滑肌细胞肌动蛋白(α-SMA)的表达.结果 培养至4～5d组织块边缘即有少量细胞爬出,呈长梭形,胞质丰富;培养至1～2周组织块边缘细胞融合,呈典型的“峰谷”样表现.免疫荧光染色结果显示胞质内α-SMA的表达丰富,荧光强度在(++)～ (+++).结论 胶原酶预处理组织的改良组织块贴壁法培养人主动脉血管平滑肌细胞是一种可行有效的实验方法.     

Involvement of Rho-kinase in the contractile mechanism of human ureteral smooth muscle

AIM: Even though many agents have been implicated as modulators of ureteral contractile activity, the exact mechanisms that control human ureteral smooth muscle contractility have yet to be clearly defined. Recently, Rho-kinase has been reported to be involved in the contractile mechanism of smooth muscles in various organs. In the present study, we sought to investigate whether or not Rho-kinase is expressed in the human ureteral smooth muscle, and to study its role regarding human ureteral smooth muscle contractility. METHODS: Ureteral samples were obtained from human adult subjects undergoing radical nephrectomy. Immunohistochemistry and Western blotting were performed to determine the presence of Rho-kinase in human ureter. Functional studies were performed with human ureteral strips suspended in organ bath, and the effects of Y-27632, a specific inhibitor of Rho-kinase, on baseline tensions, spontaneous contractions, and electrical field stimulation (EFS)-induced contractions were analyzed. RESULTS: The results of immunohistochemistry and immunoblotting study indicated that Rho-kinase is present in human ureteral smooth muscle. In functional analysis, Y-27632 was shown to decrease the baseline tension. And, both spontaneous and EFS-induced contractile responses of human ureteral strips were attenuated by Y-27632 in dose-dependent manners. CONCLUSIONS: For the first time, the results of the present study indicate that Rho-kinase is present in human ureteral smooth muscle and may play an important role in the intricate mechanism of human ureteral contractility and tone.     

人脐动脉平滑肌细胞复合脱细胞基质构建海绵体平滑肌的动物实验研究

目的 探讨脐动脉平滑肌细胞(HUASMC)与阴茎海绵体脱细胞基质(ACCM)复合构建海绵体平滑肌的可行性.方法 以1%的Triton-X100与0.1%NH3H2O混合液对兔阴茎海绵体进行脱细胞处理,制备ACCM.采用贴块法分离、培养、扩增HUASMC.HUASMC以30×10<'6>/ml密度接种ACCM,细胞-ACCM体外复合10 d后将复合物植入9只5周龄BALB/C裸鼠背部皮下,术后10、20和40 d分别对移植物进行HE染色、免疫组织化学染色和器官浴槽实验,评价其裸鼠体内构建情况.结果 ACCM为白色圆柱状,镜下为富含胶原的疏松多孔结构,不含细胞成分.HUA-SMC与ACCM相容性良好,HUASMC在与ACCM接触部位充分伸展,并沿ACCM窦隙活跃生长.9只裸鼠均存活,植入部位无感染,无植入物排斥发生.随培育时间延长,裸鼠体内ACCM逐渐降解,植入的HUASMC分化形成结构良好、交错排列的平滑肌组织.器官浴槽实验显示,构建组织对去氧肾上腺素和电刺激均表现出收缩功能,去氧肾上腺素和电刺激所诱导的最大收缩力分别为(3.64±0.18)和(2.50±0.21)g.结论 HUASMC作为种子细胞与ACCM复合可构建出具有一定形态和功能的组织工程海绵体平滑肌.     

The effect of six different statins on the proliferation, migration, and invasion of human smooth muscle cells

Intimal hyperplasia (IH) can occur after any vascular injury and results from smooth muscle cells (SMC) proliferation, migration, and invasion into the subintimal space. The purpose of this study was to investigate the effect of six different statins on the proliferation, migration, and invasion of human venous SMC. The statins were all used at their Cmax concentrations. SMCs were used to construct growth curves in the presence of 10% fetal calf serum or 10% fetal calf serum supplemented with the six statins. Migration and invasion experiments were performed using modified Boyden chambers. The invasion experiments were performed using Matrigel coated plates. We found that all of the statins significantly inhibited SMC proliferation compared to the platelet-derived growth factor control (ranging from fluvastatin 33% of control to pravastatin 72% of control, P = 0.03). SMC migration through uncoated polycarbonate membranes in presence of the six statins was significantly reduced (ranging from lovastatin 43% to pravastatin 57% of control, P = 0.006). All six statins also significantly reduced SMC invasion (ranging from fluvastatin 65% to simvastatin 87% of control, P = 0.002). We conclude that the inhibitory effect of statins on SMC proliferation, migration, and invasion is a class, rather than drug specific effect.     

人阴茎海绵体平滑肌细胞三维培养模型的建立

目的 观察人阴茎海绵体平滑肌细胞(hCCMCs)在三维培养系统中的生物学特性.方法 体外分离hCCMCs,并用差速贴壁法进行纯化.免疫组化的方法检测α-平滑肌肌动蛋白(α-SMA)的表达,进行hCCMCs的鉴定.在单层贴壁培养的基础上,将hCCMCs在胶原凝胶中培养,形成三维培养系统,并对hCCMCs的形态结构、增殖情况进行研究.结果 原代培养的hCCMCs细胞形态不均一,经过差速贴壁法纯化后,细胞形态均一,免疫组化显示大多数细胞α-SMA阳性表达.三维培养系统中,hCCMCs在不同层面上呈三维生长.hCCMCs在三维培养系统中培养10d后,细胞数量无明显增殖(P>O.05),明显低于贴壁培养条件下细胞增殖速率(P<0.01).结论 hCCMCs三维培养系统可以观察hCCMCs在三维条件下的生长、增殖状况,研究hCCMCs与微环境的相互作用关系,有望为相关研究找到一种更为简单、可控性更强的体内实验替代方法.     

人内皮型一氧化氮合成酶基因重组腺病毒载体构建及其在人血管平滑肌细胞的表达

目的 利用AdMax腺病毒载体系统构建人内皮型一氧化氮合成酶基因(heNOS)重组腺病毒并检测其在体外培养人血管平滑肌细胞中表达.方法 将质粒PMSCV-heNOS通过聚合酶链反应(PCR)法扩增出heNOS全长基因,插入PSUCMV中构建成腺病毒穿梭质粒PSUCMV-heNOS,转化DH5α大肠杆菌,挑选细菌单克隆进行DNA测序,酶切鉴定正确;通过PSUCMV-heNOS与质粒pBHGE3在293细胞中同源重组,得到携带heNOS基因的复制缺陷型重组腺病毒载体(AdCMV-he-NOS).转染体外培养的人血管平滑肌细胞,MTT检测细胞增殖,用免疫组织化学和Western blot等方法检测heNOS蛋白的表达.结果 (1)PCR产物电泳结果,酶切鉴定和测序鉴定结果证实构建人eNOS重组腺病毒载体成功,病毒滴度达3.5×l010PFU/ml;(2)根据体外培养的人血管平滑肌细胞(HVSMCs)形态学变化,免疫组织化学进行平滑肌细胞表型标志物α-actin染色,证实为HVSMCs;(3)转染120 h,AdCMV-heNOS病毒感染复数(MOI)分别为50、150、250、300、450、A570值分别为1.410±0.081、1.357±0.150、1.303±0.311、0.995±0.248、0.731±0.101,其中感染复数300明显稳定抑制血管平滑肌细胞的增殖,差异有统计学意义(P＜0.01).免疫组织化学和Western blot检测显示转染细胞heNOS蛋白明显表达.结论 heNOS重组腺病毒的构建及其表达为血管内膜增生等疾病的基因治疗提供可能.

Abstract：

Objective To construct recombinant adenovirus vector carrying the human endothelial nitric oxide synthase gene (heNOS) and detect its expression in human vascular smooth muscle cells in vitro. Methods heNOS was cloned by polymerase chain reaction (PCR) using plasmid PMSCV-heNOS,heNOS cDNA was inserted into adenovirus shuttle plasmid-PSUCMV to generate a recombinant plasmid PSUCMV-heNOS, transfected into E. coli DH5α, and positive clones were correctly constructed and confirmed by DNA sequencing analysis and restriction endonucleas analysis. The plasmid PSUCMV-heNOS was co-transfected with pBHGE3 in 293 cells to generate replication-defective recombinant adenovirus vector carrying heNOS gene. Human vascular smooth muscle cells were transfected by Ad-heNOS. The effect on the proliferation of human vascular smooth muscle cells was investigated by MTT assay. The expression of heNOS was detected by immunohistochemistry staining and Western blotting. Results ( 1 ) PCR, restrictive digestion, and sequencing revealed the successful construction of the recombinant adenovirus vector carrying heNOS gene and its titer was 3.5 × 1010 PFU/ml; (2) It was confirmed that the human vascular smooth muscle cells cultivated in vitro were characterized by morphology and immunohistochemistry strain of α-actin; (3) At 120 h, the A570 values in multiplicity of infection (MOI) 50, 150,250,300,450 were respectively 1. 410 ±0. 081, 1. 357 ±0. 150, 1.303 ±0. 311,0. 995 ±0. 248 and 0. 731 ±0. 101. The proliferation of human vascular smooth muscle cells was significantly and stably inhibited with MOI 300 of AdCMVheNOS ( P ＜ 0. 01 ). Immunostaining and Western blotting with heNOS in engineered cells were positive.Conclusion The successful construction of AdCMV-heNOS and expression may provide an opportunity for the gene therapy of vascular intimal hyperplasia.     

罗比卡因及钙通道阻断药对乙酰胆碱诱发兔离体气管平滑肌收缩影响的比较

目的研究罗比卡因及钙通道阻断药对乙酰胆碱诱发兔离体气管平滑肌收缩的影响。方法用0.1mmol/L乙酰胆碱诱发离体气管平滑肌收缩,采用自身对照,分别研究0.01mmol/L佩尔地平、0.1mmol/L地尔硫卓及1mmol/L罗比卡因对其的影响。结果1mmol/L罗比卡因在3min左右可使张力下降30%～40%,10min左右使张力基本下降至基线。钙通道阻断药佩尔地平、地尔硫卓对乙酰胆碱诱发兔离体气管平滑肌收缩无明显影响。结论罗比卡因对乙酰胆碱诱发的收缩具有明显的抑制作用,而临床上常用的钙通道阻断药佩尔地平及地尔硫卓则无明显的气道扩张作用。     

不同浓度的咪唑安定对兔离体气管平滑肌收缩的影响

目的研究不同浓度的咪唑安定对离体气管平滑肌的舒张作用,以明确咪唑安定在10-5mol/L浓度时是否能够产生较为明显的舒张作用。方法用高浓度氯化钾、乙酰胆碱、电脉冲三种刺激因素诱发兔离体气管平滑肌收缩,并观察三种不同浓度的咪唑安定对其的影响。结果1.5×10-5mol/L的咪唑安定对三种刺激因素诱发的气管平滑肌收缩不产生明显抑制作用;1.5×10-4mol/L和3.0×10-4mol/L的咪唑安定可显著抑制上述三种刺激因素诱发的气管平滑肌收缩(P<0.05或P<0.01),普萘洛尔和中枢性苯二氮卓艹类受体阻断药氟马西尼不能拮抗咪唑安定对气管平滑肌的舒张作用。结论咪唑安定在10-5mol/L左右的浓度时对兔离体气管平滑肌收缩不能产生明显的抑制作用。     

A new enzymic method for the isolation and culture of human bladder body smooth muscle cells

Cultured cells of the human urinary bladder smooth muscle are useful for investigating bladder function, but methods for culturing them are not well developed. We have now established a novel enzymic technique. The smooth muscle layer was separated out and incubated with 0.2% trypsin for 30 min at 37 degrees C. The samples were then minced and incubated with 0.1% collagenase for 30 min and centrifuged at 900 g. The pellets were resuspended in RPMI-1640 medium containing 10% fetal calf serum (FCS) and centrifuged at 250 g. The smooth muscle cells from the supernatant were cultured in RPMI-1640 containing 10% FCS. The cells grew to confluence after 7-10 days, forming the "hills and valleys" growth pattern characteristic of smooth muscle cells. Immunostaining with anti-alpha-actin, anti-myosin, and anti-caldesmon antibodies demonstrated that 99% of the cells were smooth muscle cells. To investigate the pharmacological properties of the cultured cells, we determined the inhibitory effect of muscarinic receptor antagonists on the binding of [3H]N-methylscopolamine to membranes from cultured cells. The pKi values obtained for six antagonists agreed with the corresponding values for transfected cells expressing the human muscarinic M2 subtype. Furthermore, carbachol produced an increase in the concentration of cytoplasmic free Ca2+ an action that was blocked by 4-diphenylacetoxy-N-methylpiperidine methiodide, an M3 selective antagonist. This result suggests that these cells express functional M3 muscarinic receptors, in addition to M2 receptors. The subcultured cells therefore appear to be unaffected by our new isolation method.     

利多卡因对气管平滑肌舒张作用的研究

利多卡因是临床上常用的局部麻醉药和抗室性心律失常药物;除此之外,利多卡因还具有较强的扩张气道、抑制气道炎症、降低气道高反应性的作用。此方面的研究最早可追溯到上世纪60年代,利多卡因在围术期预防和处理支气管痉挛中所占的地位已得到充分肯定,现将近10余年来利多卡因对气道平滑肌影响的主要研究成果综述如下。     

Effects of ultraviolet light on the tension of isolated human cavernosal smooth muscle from non-diabetic and diabetic impotent men

The effects of ultraviolet (UV) light (310 nm) on human cavernosal smooth muscles were investigated. Cavernosal strips were obtained from men during penile prosthetic surgery. When the cavernosal strips were irradiated with UV light in an organ bath, after precontraction by norepinephrine (100 nM) for 10, 20, 40 and 90 s at intervals of 3 min, the contracted cavernosal smooth muscles from the impotent men without vascular risk factors (controls) showed relaxation depending on the duration of irradiation. However, the relaxation was not found when the strips were pretreated with methylene blue (10 M) or their epithelia were denuded. The relaxation response of the cavernosal strips from the patients with diabetogenic impotence was significantly reduced compared with that of the controls. Photorelaxation of human cavernosal strips therefore seems to be dependent on endothelium.     

Small lungs and suspect smooth muscle: congenital diaphragmatic hernia and the smooth muscle hypothesis

Lung hypoplasia and congenital diaphragmatic hernia (CDH) represent an unsolved clinical and scientific problem. Early lung morphogenesis is coupled to development and function of pulmonary smooth muscle. Activity of the latter is abnormal from the earliest stages of hypoplastic lung development and before supervening CDH. A “smooth muscle hypothesis” is advanced to help explain embryonic lung malformations, fetal failure of lung growth, and postnatal susceptibility to barotrauma, airway hyperreactivity, and pulmonary hypertension in CDH. Exploring the interaction of smooth muscle function and airway pressures may help optimise tracheal occlusion and provide support for both an adequately powered trial of glucocorticoids and also for experimental “preventilation” strategies in fetal CDH.     

Ca2+ sensitization in contraction of human bladder smooth muscle

PURPOSE: The role of Ca2+ sensitization in the contraction of human bladder urinary smooth muscle (UBSM) was investigated. MATERIALS AND METHODS: Simultaneous measurements of intracellular Ca2+ concentration ([Ca2+]i) and tension in fura-2 loaded intact strips and receptor coupled strips permeabilized with alpha-toxin were applied. Protein expressions was confirmed by Western blot analysis. RESULTS: In intact fura-2 loaded strips 1 microM carbachol (CCh) induced a greater contraction and a lower [Ca2+]i elevation than that induced by 60 mM K depolarization. In alpha-toxin permeabilized strips 1 microM CCh induced contraction at constant [Ca2+]i and produced a leftward shift in the [Ca2+]i-tension relationship. RhoA, Rho-associated kinase (ROCK) I, ROCK II and CPI-17 proteins were expressed in human UBSM. In intact fura-2 loaded strips the application of 3 microM Y-27632, a ROCK inhibitor, or 3 microM bisindolylmaleimide I (GF109203X), a protein kinase C inhibitor, during the sustained phase of contraction induced by 1 microM CCh induced relaxation without changing [Ca2+]i. In alpha-toxin permeabilized strips the application of 3 microM Y-27632 or 3 microM GF109203X during the sustained contraction induced by 0.3 microM Ca plus 10 microM guanosine triphosphate and 1 microM CCh induced relaxation at constant [Ca2+]i. CONCLUSIONS: These results indicate that in human UBSM CCh induces contraction, not only by increasing [Ca2+]i, but also by increasing the Ca2+ sensitivity of the contractile apparatus in a ROCK and protein kinase C dependent manner. Antagonism of Ca2+ sensitization pathways may represent an alternative target in the treatment of overactive bladder.