ha-1100 and Hypertension

To investigate the effect of hydroxyfasudil, a nonselective Rho-kinase inhibitor, on hypertension-related bladder dysfunction in spontaneously hypertensive rats (SHRs), as there is an increasing evidence that the Rho-associated protein kinase (ROCK) system plays an important role in bladder contraction.. Twelve-week-old male SHRs were treated with hydroxyfasudil (1 mg/kg i.p.) once a day for 6 weeks. Wistar rats and SHRs without treatment with hydroxyfasudil were used as controls. Six weeks after the hydroxyfasudil treatment, voiding functions were evaluated by metabolic cages and cystometric studies under urethane anesthesia (1.0 g/kg i.p.). Bladder blood flow (BBF) was estimated by the hydrogen clearance method. The bladder tissue levels of nerve growth factor (NGF) and ROCK activity were evaluated by the ELISA method.. The SHR showed significant increases in micturition frequency and decreases in single-voided volume in metabolic cages, and significantly increases in micturition frequency and intercontractile interval in cystometric studies. Furthermore, the SHR showed significant increases in the BBF and bladder NGF concentration compared with the Wistar rats. These alterations in the SHR were significantly ameliorated after treatment with hydroxyfasudil, with small changes in blood pressure. However, the maximum detrusor pressures during voiding and the ROCK activities in the experimental bladders were similar in all rats examined.. Our data indicate that this dose of hydroxyfasudil was effective on the BBF, whereas it had no significant effect on micturition pressure. These findings suggest that hydroxyfasudil could ameliorate hypertension-related bladder dysfunction in the SHR via improvement of the BBF (248 words).

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Hypertension; Male; Muscle Contraction; Muscle, Smooth; Nerve Growth Factor; Rats; Rats, Inbred SHR; Rats, Wistar; Regional Blood Flow; rho-Associated Kinases; Urinary Bladder; Urination; Urodynamics

Hypertension represents a major risk factor for erectile dysfunction. Although the etiology of hypertension-induced erectile dysfunction is multifactorial and still unknown, Rho-Rho kinase pathway is one of the key factors. To investigate whether administration of hydroxyfasudil, a Rho kinase inhibitor could prevent dysfunction of NO-induced relaxation in corpus cavernosum smooth muscle in the SHR (spontaneously hypertensive rat), twelve-week-old male SHRs were treated with hydroxyfasudil (3 or 10 mg/kg, i.p.) once a day for 6 weeks. Wistar rats and SHRs treatment with vehicle were used as age-matched controls. Penile cGMP concentrations and Rho kinase activities were determined, and penile function was estimated by organ bath studies with norepinephrine-induced contractions and acetylcholine-induced relaxations. The participation mRNA levels of eNOS and participation protein levels of eNOS and phosphorylated eNOS were investigated by quantitative real-time PCR methods and immunoblot analysis, respectively. The SHR showed significantly decreased cGMP concentrations, increased Rho kinase activities, norepinephrine-induced hyper-contractions, and acetylcholine-induced hypo-relaxations in the penile tissue. Treatment with hydroxyfasudil significantly improved the decreased penile cGMP concentrations, the increased Rho kinase activities, the increased norepinephrine-induced contractions, and the decreased acetylcholine-induced relaxation in a dose-dependent manner. Although there were no significant differences in expression protein levels of eNOS among any of the groups, down-regulation of eNOS mRNAs as well as phosphorylated eNOS were significantly ameliorated after treatment with hydroxyfasudil. Our data suggest that hydroxyfasudil ameliorates hypertension-associated dysfunction of NO-induced relaxation in corpus cavernosum smooth muscle possibly via inhibition of the Rho-Rho kinase pathway and activation of NO-eNOS pathway in the SHR.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Cyclic GMP; Erectile Dysfunction; Gene Expression Regulation; Hypertension; Male; Nitric Oxide Synthase Type III; Penis; Phosphorylation; Rats; Rats, Inbred SHR; Rats, Wistar; rho-Associated Kinases; RNA, Messenger

Rho-kinase plays an important role in hypertension and is reported to interfere with insulin signaling through serine phosphorylation of insulin receptor substrate-1 (IRS-1) in cultured vascular smooth muscle cells. We therefore examined the role of Rho-kinase in the development of insulin resistance in Zucker obese rats. In skeletal muscles and aortic tissues of Zucker obese rats, activation of RhoA/Rho-kinase was observed. Long-term Rho-kinase inhibition by 4 wk treatment with fasudil (a Rho-kinase inhibitor) not only reduced blood pressure but corrected glucose and lipid metabolism, with improvement in serine phosphorylation of IRS-1 and insulin signaling in skeletal muscles. Direct visualization of skeletal muscle arterioles with an intravital CCD videomicroscope demonstrated that both acetylcholine- and sodium nitroprusside-induced vasodilations were blunted, which were restored by the fasudil treatment. Furthermore, both fasudil and Y-27632 prevented the serine phosphorylation of IRS-1 induced by insulin and/or tumor necrosis factor-alpha in skeletal muscle cells. Collectively, Rho-kinase is responsible for the impairment of insulin signaling and may constitute a critical mediator linking between metabolic and hemodynamic abnormalities in insulin resistance.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Acetylcholine; Animals; Arterioles; Cell Line; Glucose Tolerance Test; Hypertension; Insulin; Insulin Resistance; Intracellular Signaling Peptides and Proteins; Muscle, Skeletal; Nitroprusside; Protein Serine-Threonine Kinases; Protein Transport; Rats; Rats, Zucker; rho-Associated Kinases; rhoA GTP-Binding Protein; Signal Transduction; Tumor Necrosis Factor-alpha

Intracellular signaling pathway mediated by small GTPase Rho and its effector Rho-kinase plays an important role in regulation of vascular smooth muscle contraction and other cellular functions. We have recently demonstrated that Rho-kinase is substantially involved in angiotensin II-induced gene expressions and various cellular responses in vitro. However, it remains to be examined whether Rho-kinase is involved in the angiotensin II-induced cardiovascular hypertrophy in vivo and, if so, what mechanisms are involved. Long-term infusion of angiotensin II for 4 weeks caused hypertrophic changes of vascular smooth muscle and cardiomyocytes in rats. Both changes were significantly suppressed by concomitant oral treatment with fasudil, which is metabolized to a specific Rho-kinase inhibitor, hydroxyfasudil, after oral administration. Angiotensin II caused a perivascular accumulation of macrophages and Rho-kinase activation, both of which were also significantly suppressed by fasudil. Vascular NAD(P)H oxidase expression (nox1, nox4, gp91phox, and p22phox) and endothelial production of superoxide anions were markedly increased by angiotensin II, both of which were also significantly suppressed by fasudil. Thus, fasudil ameliorated the impaired endothelium-dependent relaxations caused by angiotensin II without affecting vasodilator function of vascular smooth muscle. These results provide evidence that Rho-kinase is substantially involved in the angiotensin II-induced cardiovascular hypertrophy in rats in vivo. The suppression of endothelial NAD(P)H oxidase upregulation and resultant superoxide production and the amelioration of endothelial vasodilator function may be involved in this process.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Angiotensin II; Animals; Aorta, Thoracic; Cardiomegaly; Cell Movement; Coronary Vessels; Endothelium, Vascular; Enzyme Inhibitors; Hypertension; Intracellular Signaling Peptides and Proteins; Macrophages; Male; NADPH Oxidases; Organ Culture Techniques; Protein Serine-Threonine Kinases; Rats; Rats, Inbred WKY; rho-Associated Kinases; Superoxides; Vasoconstrictor Agents; Vasodilation

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Blood Vessels; Cardiovascular Diseases; Hypertension; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Male; Protein Serine-Threonine Kinases; Rats; Rats, Inbred SHR; Rats, Inbred WKY; rho-Associated Kinases; Signal Transduction; Vascular Resistance; Vasoconstriction; Vasodilator Agents