Effect of Doxazosin With and Without Rho-Kinase Inhibitor on Human Corpus Cavernosum Smooth Muscle in the Presence of Bladder Outlet Obstruction

Numerous studies have now demonstrated that lower urinary tract symptoms (LUTS) are associated with erectile dysfunction (ED) in men independent of age or general health. Because one-third of men over the age of 50 will develop LUTS and a recent study showed ED in 62% of patients presenting for LUTS, the importance of determining the mechanistic link between these two pathologies is clear. Using a rabbit model of partial bladder outlet obstruction (PBOO), a primary cause of LUTS, we have identified an increased basal corpus cavernosum smooth muscle (CCSM) tone associated with an elevated level of smooth muscle myosin (SMM) phosphorylation in PBOO compared with sham-operated control rabbits (sham). Results from in vitro kinase and phosphatase assays using purified smooth muscle myosin showed increased kinase and decreased phosphatase activities in cellular extracts from corpora cavernosa isolated from PBOO compared with sham rabbits. Increased Rho-kinase expression in the CCSM of PBOO rabbits was suggested by the observations that Rho-kinase inhibitors attenuated the increased kinase activity and were less effective in relaxing CCSM strips from PBOO vs. sham rabbits. This hypothesis was then confirmed by RT-PCR and Western blotting, which demonstrated increased expression of both isoforms of Rho-kinase (ROKα and ROKβ). Increased SMM basal phosphorylation (necessary for SM contraction) in the CCSM of PBOO rabbits, mediated via an increase in Rho-kinase expression/activity, would be expected to make the CCSM more difficult to relax (necessary for erection), which suggests that the RhoA/Rho-kinase pathway as being involved in the mechanism for LUTS-associated ED.

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Re: Effects of Oral Rho Kinase Inhibitor Fasudil on Detrusor Overactivity after Bladder Outlet Obstruction in Rats

The Journal of Urology ◽

10.1016/j.juro.2013.10.020 ◽

2014 ◽

Vol 191 (1) ◽

pp. 272-272

Author(s):

Alan J. Wein

Keyword(s):

Detrusor Overactivity ◽

Bladder Outlet Obstruction ◽

Kinase Inhibitor ◽

Rho Kinase ◽

Outlet Obstruction ◽

Rho Kinase Inhibitor

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Abstract 641: Expression Of GLUT4 In Vascular Smooth Muscle Affects Endothelial Function In Hypertension.

Hypertension ◽

10.1161/hyp.62.suppl_1.a641 ◽

2013 ◽

Vol 62 (suppl_1) ◽

Author(s):

Kevin B Atkins ◽

Jharna Saha ◽

Frank C Brosius

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Kinase Inhibitor ◽

Rho Kinase ◽

Interesting Phenomenon ◽

Glut4 Expression ◽

Endothelial Denudation ◽

Rho Kinase Inhibitor ◽

Total Body ◽

Rats And Mice

Expression of GLUT4 is decreased in arterial smooth muscle of hypertensive rats and mice, and total body overexpression of GLUT4 in mice prevents enhanced arterial reactivity. To demonstrate that the effect on vascular response to GLUT4 overexpression is vascular rather than systemic in origin we utilized smooth muscle-specific GLUT4 transgenic mice (SMG4). GLUT4 expression in aortae of SMG4 compared to WT mice was increased 2-3 fold. Adult wild-type (WT) and SMG4 mice were made hypertensive or not through implantation of angiotensin II (AngII; 1.4mg/kg/d for 2 wks) or vehicle containing osmotic mini-pumps. Both WT and SMG4 mice AngII-treated mice exhibited significantly increased systolic blood pressure. In AngII-treated WT mice (WT-AngII) aortic GLUT4 expression was significantly decreased, whereas GLUT4 expression in aortae of AngII-treated SMG4 mice (SMG4-AngII) was maintained. The phosphorylation of ERM and MYPT1(Thr850) were significantly increased in aortae of WT-AngII compared to WT-Sham and SMG4-AngII mice. Responsiveness to the contractile agonists, phenylephrine, 5-HT, and PGF 2 was significantly increased in endothelium-intact aortic rings from WT-AngII mice, but remained normal in aortae of SMG4-AngII mice. Following pretreatment with Rho-kinase inhibitor Y-27632, relative inhibition of contractility to 5-HT was equal in aortae from WT-AngII and SMG4-AngII-treated mice. With endothelial denudation, contractility to 5-HT was equally enhanced in aortae of WT-AngII and SMG4-AngII-treated mice. Interestingly, whereas acetylcholine stimulated relaxation was significantly decreased in aortic rings of WT-AngII mice, relaxation in rings from SMG4-AngII mice was not significantly different from WT or SMG4. These results demonstrate an interesting phenomenon whereby decreased expression of GLUT4 in vascular smooth muscle leads to an endothelial dysfunction that not only impairs relaxation, but also enhances contractility.

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RhoA-Rho kinase mediates synergistic ET-1 and phenylephrine contraction of rat corpus cavernosum

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00329.2003 ◽

2003 ◽

Vol 285 (5) ◽

pp. R1145-R1152 ◽

Cited By ~ 40

Author(s):

Christopher J. Wingard ◽

Shahid Husain ◽

Jan Williams ◽

Sharita James

Keyword(s):

Kinase Inhibitor ◽

Corpus Cavernosum ◽

Rho Kinase ◽

Stress Generation ◽

Combined Stress ◽

Fourfold Increase ◽

Rho Kinase Inhibitor ◽

Tissue Homogenates ◽

Dose Dependent ◽

Kinase Pathway

Maintenance of the detumescent state of the penis is believed to involve the actions of several vasoconstrictors. However, our mechanistic understanding of any synergistic vasoconstrictor influences is extremely limited. We tested the hypothesis that a vasoconstrictor combination of endothelin (ET-1) and phenylephrine (PE) augments the constrictor responses in rat corporal cavernosal tissues by a mechanism involving the RhoA-Rho kinase pathway. Independently, ET-1 (1 nM-30 μM) and PE (100 nM-100 μM) both caused dose-dependent contractions of isolated rat cavernosal tissues. In combination, ET-1 (30 nM) augmented the contractile effect of PE and shifted the calculated EC50 for PE (90 ± 12 to 45 ± 5 μM). The active stress generated by cavernosal strips during the ET-1 + PE combined stimulation (4.9 ± 0.2 mN/mm2) was greater than the combined stress generated with ET-1 (0.4 ± 0.1 mN/mm2) or PE (3.3 ± 0.2 mN/mm2) stimulations alone. Blockade of ETA receptors (30 nM; A-127722) reversed the augmented stress generation and the Rho-kinase inhibitor Y-27632 differentially and dose-dependently relaxed the tissue. The combined constrictor effect was associated with a fourfold increase of RhoA in the membrane faction of the tissue homogenates. We conclude that the ET-1 + PE combination potentiate vasoconstriction through mutual activation of the RhoA-Rho kinase pathway. The interactions of these agonists likely play important roles in the maintenance of the flaccid state and contribute to some forms of erectile dysfunction.

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Resveratrol’s Impact on Vascular Smooth Muscle Cells Hyporeactivity: The Role of Rho-Kinase Inhibition

BioMed Research International ◽

10.1155/2020/9012071 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Michał Wiciński ◽

Bartosz Malinowski ◽

Paweł Rajewski ◽

Paweł Szychta ◽

Eryk Wódkiewicz ◽

...

Keyword(s):

Smooth Muscle ◽

Protein Kinases ◽

Vascular Smooth Muscle Cells ◽

Kinase Inhibitor ◽

Rho Kinase ◽

Pressure Effects ◽

Kinase Inhibition ◽

Rho Kinase Inhibitor ◽

Dependent Protein

Resveratrol (3,5,4′-trihydroxystilbene) is a chemical compound belonging to the group of polyphenols and flavonoids. The aim of the present study was to determine the influence of resveratrol application along with certain modulating factors, such as 8Br-cGMP-activator of cGMP-dependent protein kinases, HA-1077-Rho-kinase inhibitor, and Bay K8644-calcium channel agonist, on VMSCs constriction triggered by phenylephrine. Resveratrol at a dose of 10 mg/kg/24 h administered for 4 weeks reduced the reactivity of the arteries to the pressure action of catecholamines. Tests performed after four weeks of resveratrol administration showed that 8Br-cGMP at the concentrations of 0.01 mM/l and 0.1 mM/l intensifies this effect. Simultaneous resveratrol and Bay K8644 administration led to a significant decrease in contractility compared to the vessels collected from animals (Res−). This effect was dependent on the concentration of Bay K8644. Resveratrol seems to be counteractive against Bay K8644 by blocking L-type calcium channels. As the concentration of HA-1077 increased, there was a marked hyporeactivity of the vessels to the pressure effects of phenylephrine. The results indicate synergy between resveratrol and Rho-kinase inhibition.

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Animal model for angiotensin II effects in the internal anal sphincter smooth muscle: mechanism of action

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00207.2001 ◽

2002 ◽

Vol 282 (3) ◽

pp. G461-G469 ◽

Cited By ~ 13

Author(s):

Ya-Ping Fan ◽

Rajinder N. Puri ◽

Satish Rattan

Keyword(s):

Smooth Muscle ◽

Protein Kinase ◽

Kinase Inhibitors ◽

Kinase Inhibitor ◽

Rho Kinase ◽

Ang Ii ◽

Kinase C ◽

Rho Kinase Inhibitor ◽

Isolated Smooth Muscle Cells

Effect of ANG II was investigated in in vitro smooth muscle strips and in isolated smooth muscle cells (SMC). Among different species, rat internal and sphincter (IAS) smooth muscle showed significant and reproducible contraction that remained unmodified by different neurohumoral inhibitors. The AT1antagonist losartan but not AT2 antagonist PD-123319 antagonized ANG II-induced contraction of the IAS smooth muscle and SMC. ANG II-induced contraction of rat IAS smooth muscle and SMC was attenuated by tyrosine kinase inhibitors genistein and tyrphostin, protein kinase C (PKC) inhibitor H-7, Ca2+ channel blocker nicardipine, Rho kinase inhibitor Y-27632 or p44/42mitogen-activating protein kinase (MAPK44/42) inhibitor PD-98059. Combinations of nicardipine and H-7, Y-27632, and PD-98059 caused further attenuation of the ANG II effects. Western blot analyses revealed the presence of both AT1 and AT2receptors. We conclude that ANG II causes contraction of rat IAS smooth muscle by the activation of AT1 receptors at the SMC and involves multiple intracellular pathways, influx of Ca2+, and activation of PKC, Rho kinase, and MAPK44/42.

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