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Katsuya Hirano

Publications and source records attributed to Katsuya Hirano.

At least 19 recordsLinked to original sources
PubMed2005

Functional role of PKC in contraction of cultured human prostatic stromal cells.

The contractile activity of prostatic stromal cells contributes to symptoms of benign prostatic hyperplasia (BPH). However, the mechanisms for this contraction have not yet been fully elucidated. In this study, we investigated the role of protein kinase C (PKC) in prostatic contraction by measuring the isometric tension development of cultured human prostatic stromal cells (CHPSCs) derived from BPH patients. Fresh human BPH tissue was used only in a Western blot analysis. A ring preparation made of CHPSCs and collagen gel could develop an isometric tension during activation with various agonists. Phorbol 12,13 dibutyrate (PDBu), a PKC activator, induced a relaxation. A Western blot analysis revealed the expression of PKC-potentiated protein phosphatase-1 inhibitory protein (CPI-17) in both CHPSCs and fresh human BPH tissue to be much lower than that in the rabbit aorta. When CPI-17 was over-expressed, PDBu induced a large contraction, but the agonist-induced contraction did not become larger than expected. In alpha-toxin permeabilized preparations, PDBu induced a relaxation in control CHPSCs, while it induced a contraction at a constant [Ca2+]i in CPI-17 over-expressing CHPSCs. These results indicated that the activation of PKC in CHPSCs induces a relaxation probably due to low expression level of CPI-17 and also that the PKC-CPI-17 pathway does not appear to play a major role in the agonist-induced contraction even when CPI-17 was over-expressed.

Animals↗
PubMed2005

Rac1 regulation of surface expression of protease-activated receptor-1 and responsiveness to thrombin in vascular smooth muscle cells.

OBJECTIVE: Protease-activated receptor-1 (PAR1) mediates the thrombin-induced proliferation and hypertrophy of vascular smooth muscle cells. A role of Rac1 in the regulation of PAR1 expression was investigated. METHODS AND RESULTS: Treatment with simvastatin, a hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitor, for 24 hours attenuated the transient [Ca2+]i elevation induced by thrombin. Immunofluorescence staining revealed that simvastatin decreased the surface expression of PAR1 in a manner dependent on protein geranylgeranylation. Introduction of a Rac1/Cdc42 inhibitory fragment but not a RhoA inhibitory fragment using a cell-penetrating peptide also attenuated the response to thrombin and decreased the surface expression of PAR1. Finally, downregulation of Rac1, but not RhoA, using an RNA interference technique attenuated the thrombin-induced [Ca2+]i elevation. However, the level of PAR1 mRNA and the total amount of PAR1 protein remained unchanged. CONCLUSIONS: Here, we provide for the first time 3 lines of evidence that Rac1 plays a critical role in maintaining the surface expression of PAR1 and the responsiveness to thrombin in vascular smooth muscle cells. Rac1 is suggested to regulate the constitutive trafficking of PAR1 and thereby regulate the surface expression of PAR1.

Animals↗
PubMed2005

Long-term inhibition of RhoA attenuates vascular contractility by enhancing endothelial NO production in an intact rabbit mesenteric artery.

RhoA plays a critical role in regulating NO production in cultured endothelial cells. To determine its role in in situ endothelial cells, we investigated the effects of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors and a RhoA-binding domain of Rho-kinase (RB) on vascular contractility in the isolated rabbit mesenteric artery. Ex vivo treatment of the strips with 3x10(-5) mol/L simvastatin and fluvastatin for approximately 24 to 30 hours significantly attenuated the contractile response to phenylephrine and high K+ in the presence of endothelium. The addition of N(omega)-nitro-L-arginine methyl ester and the removal of endothelium abolished the attenuation of the contractile response. The cotreatment with geranylgeranyl pyrophosphate prevented the statin-induced attenuation of the contractile response, whereas geranylgeranyl transferase inhibitor mimicked the effect of simvastatin. Treatment with simvastatin enhanced the bradykinin-induced endothelium-dependent relaxation in the mesenteric artery, whereas it had no effect on the bradykinin-induced [Ca2+]i elevation in endothelial cells of the aortic valves. Introduction of RB to the strips using a cell-penetrating peptide of Tat protein (TATHA-RB) attenuated the contractile responses in a NO-dependent manner. However, a Rac1/Cdc42-binding fragment of p21-activated protein kinase, RB without Tat peptide or TATHA-protein A had no effect. The in vivo treatment of rabbit with simvastatin and TATHA-RB attenuated the contractility in a NO-dependent manner. Simvastatin and TATHA-RB significantly upregulated eNOS in the rabbit mesenteric artery. The present study provides the first evidence that RhoA plays a physiological role in suppressing NO production in in situ endothelial cells.

Animals↗
PubMed2005

Contractile properties of the cultured vascular smooth muscle cells: the crucial role played by RhoA in the regulation of contractility.

Vascular smooth muscle cells (VSMCs) have a remarkable degree of plasticity and in response to vascular injury, they can change to a dedifferentiated state that can be typically seen in cell cultures. Recently, Y27632, a Rho kinase inhibitor, has been reported to preferentially correct hypertension in a hypertensive rat model. We thus tested the hypothesis that the contraction of the cultured VSMCs might be more dependent on the function of RhoA than the VSMCs in fresh tissue. For this purpose, a tissue-like ring preparation was made using the cultured porcine coronary artery SMCs (CASMCs) and collagen gel (reconstituted ring: R-ring). The R-ring developed an isometric tension on stimulation by high external K+ or various receptor agonists. The phorbol ester (a protein kinase C (PKC) activator)-induced contraction of the intact R-ring was greatly inhibited, while the GTPgammaS (an activator of RhoA)-induced and Ca2+-independent contraction of permeabilized R-ring was greatly enhanced, in comparison to the fresh coronary artery ring. An immunoblot analysis showed the expression levels of RhoA and myosin phosphatase subunits (MYPT1 and PP1cdelta) to be up-regulated, while the levels of CPI-17 (PKC-potentiated protein phosphatase-1 inhibitory protein), h1-calponin and PKC isoforms were downregulated in cultured CASMCs. The knock down of RhoA by RNA interference decreased the contractility of the cultured CASMCs. It is concluded that the contractility of the cultured VSMCs thus appears to be much more dependent on the function of RhoA than VSMCs in fresh tissue. The expression level of RhoA thus plays a crucial role in regulating the contractility of cultured VSMCs.

Amides↗
PubMed2005

Physiology and pathophysiology of proteinase-activated receptors (PARs): regulation of the expression of PARs.

The level of receptors expressed on the cell surface determines the cellular responsiveness to agonists. Proteinase-activated receptors (PARs) have been reported to be either up-regulated or down-regulated in response to various types of stimulation and pathological situations. In addition, the transcriptional regulation plays a major role in the alteration of the expression of PARs under pathological conditions, while post-translational mechanisms such as phosphorylation, arresting-binding, internalization, and lysosomal degradation, which desensitize activated PARs and terminate intracellular signaling, also play an important role in regulating the expression of PARs and the cellular responsiveness to the agonists. Elucidating the mechanisms related to the expression of PARs is a critical step to understand the pathophysiology of various diseases and establish new therapeutic strategies. However, the molecular mechanism regulating the expression of PARs still remains to be elucidated. This minireview discusses our current understanding of the mechanisms regulating the expression of PARs. The transcription factors and the regulatory elements in the promoter regions, and the proteins that interact with the receptors and thereby regulate their trafficking and desensitization are the main problems that need to be elucidated.

Animals↗
PubMed2005

The mechanism underlying the contractile effect of a chemotactic peptide, formyl-Met-Leu-Phe on the guinea-pig Taenia coli.

1 The contractile mechanism of N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) was investigated in the guinea-pig Taenia coli, by simultaneously monitoring the changes in the cytosolic Ca(2+) concentration ([Ca(2+)](i)) and force. 2 fMLP induced a significant elevation of [Ca(2+)](i) and force at concentrations higher than 10 nM. The maximal response was obtained at a concentration of higher than 1 microM. 3 fMLP (10 microM) augmented the force development induced by a stepwise increment of the extracellular Ca(2+) concentration during 60 mM K(+) depolarization, while it had no effect on the [Ca(2+)](i) elevation, and thus produced a greater force for a given elevation of [Ca(2+)](i) than 60 mM K(+) depolarization. 4 The removal of extracellular Ca(2+) completely abolished the fMLP-induced contraction. The fMLP-induced [Ca(2+)](i) elevation was inhibited substantially but not completely by 10 microM diltiazem, partly by 10 microM SK&F 96365, and completely by their combination. 5 Y27632, a specific inhibitor of rho-kinase, had no significant effect on the fMLP-induced [Ca(2+)](i) elevation and force development. 6 Chenodeoxycholic acid, a formyl peptide receptor antagonist, specifically abolished the fMLP-induced contraction but not high K(+)- or carbachol-induced contractions. 7 A dual lipoxygenase/cyclooxygenase inhibitor, a 5-lipoxygenase inhibitor, a nonselective leukotriene receptor antagonist, and a selective type 1 cysteinyl-containing leukotriene receptor antagonist specifically reduced the fMLP-induced contraction. 8 We suggest that the low-affinity-type fMLP receptor and lipoxygenase metabolites of arachidonic acid are involved in the fMLP-induced contraction in the guinea-pig T. coli. This contraction mainly depends on the [Ca(2+)](i) elevation due to Ca(2+) influx and the enhancement of Ca(2+) sensitivity in the contractile apparatus.

Animals↗
PubMed2005

Enhancement of trypsin-induced contraction by in vivo treatment with 17beta-estradiol and progesterone in rat myometrium.

We have previously reported that the contractile response to thrombin and trypsin was enhanced in the pregnant rat myometrium. We herein determined whether or not sex hormones contribute to this enhancement and the expression of protease-activated receptors (PARs). The nonpregnant rats received daily injections of either 17beta-estradiol or progesterone, and then the contractile response of the myometrium was examined ex vivo. Treatment with either 17beta-estradiol or progesterone had almost no significant enhancing effect on the high K(+)- or oxytocin-induced contraction. On the other hand, both 17beta-estradiol and progesterone dose-dependently enhanced the contractile response to trypsin. A maximal enhancement was obtained at 25 and 40 mg kg weight(-1) day(-1) for 17beta-estradiol and progesterone, respectively. The extent of the enhancement of the trypsin-induced contraction seen in the sex hormone-treated rats in the present study was comparable to that reported in the pregnant rats. However, the contractile response to thrombin and PAR1/PAR2-AP, SFLLRNP was not enhanced either by progesterone or 17beta-estradiol. PAR2-AP and PAR4-AP failed to induce contraction under any conditions. PAR1 mRNA was scarcely detected in the control myometrium by an RT-PCR analysis, while it slightly increased only in the progesterone-treated rats. Neither PAR2 nor PAR4 mRNA was detected. We thus conclude that the responsiveness to trypsin, but not thrombin, is controlled by sex hormones. A novel type of receptor, other than PAR1, PAR2 or PAR4, is suggested to mediate the trypsin-induced contraction as in the case of the pregnant rat myometrium.

Animals↗
PubMed2004

Akt plays a central role in the anti-apoptotic effect of estrogen in endothelial cells.

Estrogen has been reported to inhibit apoptosis in vascular endothelial cells. However, its precise mechanism still remains to be elucidated. Here we determined the role of Akt in the anti-apoptotic effect of estrogen. 17Beta-estradiol prevented the apoptosis induced by TNF-alpha in bovine aortic endothelial cells, as evaluated by double staining with fluorescein isothiocyanate-conjugated annexin V and propidium iodide. Introducing a dominant negative mutant of Akt by using a cell-penetrating peptide of Tat protein inhibited the anti-apoptotic effect of estrogen in a concentration-dependent manner, and resulted in the complete inhibition of the anti-apoptotic effect of 17beta-estradiol at 1nM and higher concentrations. The dominant negative mutant without the cell-penetrating peptide and Tat peptide-conjugated protein A had no effect. The intracellular protein transduction was confirmed by immunoblot analysis. Our observations thus provide first direct evidence that Akt plays a central role in the anti-apoptotic effect of estrogen in vascular endothelial cells.

Animals↗
PubMed2004

Facilitation of proteasomal degradation of p27Kip1 by N-terminal cleavage and their sequence requirements.

The sequence requirement for N-terminal cleavage and the proteasomal degradation of p27Kip1 and their relationship was investigated. Residues 5-8 were required for the cleavage and the mutation of S10 to E inhibited the cleavage. The C-terminal PEST sequence was necessary for the degradation and residue R165 was found to play an important role in the degradation. The inhibition of the cleavage by deleting residues 5-8 inhibited the degradation, while the fragment mimicking the cleavage product accelerated the degradation. Both the cleavage and degradation demonstrated a similar sensitivity toward proteasome inhibitors and ATP depletion. These two processes are thus suggested to be tightly linked and sequential.

Animals↗
PubMed2004

A critical period requiring Rho proteins for cell cycle progression uncovered by reversible protein transduction in endothelial cells.

The time-specific requirement of Rho proteins for the S phase progression of vascular endothelial cells was determined by reversibly introducing inhibitor proteins with a cell-penetrating peptide. We found evidence of the reversibility of protein transduction. The removal of extracellular protein caused the transduced protein to decay in a manner sensitive to low temperatures. The time required for a 50% decay correlated with the protein size. The time-specific transduction of the inhibitor proteins uncovered a critical period requiring Rho proteins in the G1-S transition phase. Reversible protein transduction may thus be a powerful tool to investigate the time-specific role of signaling proteins.

Animals↗
PubMed2004

Inactivation of protease-activated receptor-1 by proteolytic removal of the ligand region in vascular endothelial cells.

Proteolysis plays an important role in inactivating protease-activated receptor-1 (PAR1). We aimed to determine the cleavage site(s) responsive for the proteolytic inactivation of PAR1 in human umbilical vein endothelial cells. Fura-2 fluorometry revealed that the preceding stimulation with trypsin abolished the subsequent [Ca(2+)](i) response to thrombin, while the responses to PAR1-activating peptides remained intact. On the other hand, thrombin had no effect on the subsequent response to trypsin. The immunostaining with antibodies against the residues 35-46 (SPAN12) and 51-64 (WEDE15) revealed the broad boundaries of cleavage. Trypsin removed both epitopes from the cell surface within 3 min, while thrombin removed the epitope of SPAN12. The longer incubation with thrombin removed the epitope of WEDE15. However, PAR1-activating peptides thereafter induced an attenuated but significant elevation of [Ca(2+)](i). Not only the receptor internalization as observed with a confocal microscope, but also an additional cleavage was thus suggested to contribute to the thrombin-induced removal of the epitope of WEDE15. The analyses of the PAR1 mutants identified three cleavage sites for trypsin; residues 41-42, 70-71 and 82-83. The cleavage at the latter two sites was suggested to dominate that at the former, and thus remove the ligand region (residues 42-47). The inactivation of PAR1 due to proteolytic removal of the ligand region may contribute not only to the inactivation of PAR1 by proteases such as trypsin, but also to the termination of the intracellular signaling initiated by thrombin in the vascular endothelial cells.

Calcium Signaling↗
PubMed2004

Endothelial dysfunction and altered bradykinin response due to oxidative stress induced by serum deprivation in the bovine cerebral artery.

Oxidative stress plays a critical role in the pathogenesis of vasospasm after a subarachnoid hemorrhage. We demonstrate that 24-h incubation of the isolated bovine middle cerebral arteries in the serum-free media at 37 degrees C converted the response to bradykinin from relaxation to contraction, in a manner sensitive to free radical scavengers. In the freshly prepared strips, bradykinin induced an endothelium-dependent relaxation, while having no direct effect on the smooth muscle. However, in the strips treated in serum-free media, bradykinin failed to induce endothelium-dependent relaxation, but did demonstrate a direct contractile effect on smooth muscle. The addition of superoxide dismutase and ascorbic acid or 5% serum during the 24-h incubation in the serum-free media prevented the loss of endothelium-dependent relaxation and the development of a contractile response to bradykinin. SB203580 (4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole), a p38 mitogen-activated protein kinase inhibitor, and genistein (4',5,7-Trihydroxyisoflavone), a tyrosine kinase inhibitor, also demonstrated a similar preventive effect. In conclusion, serum-deprivation induced endothelial dysfunction and the responsiveness of smooth muscle to bradykinin due to failure of eliminating oxidative stress. p38 mitogen-activated protein kinase and tyrosine kinase were suggested to play a critical role in this endothelial dysfunction.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2004

Transduction of the N-terminal fragments of MYPT1 enhances myofilament Ca2+ sensitivity in an intact coronary artery.

OBJECTIVE: The region of the 110 kDa regulatory subunit (MYPT1) of smooth muscle myosin phosphatase involved in the regulation of contraction was determined under physiological conditions. METHODS AND RESULTS: Using HIV Tat protein-mediated protein transduction, the N-terminal fragments of MYPT1 were introduced to the intact porcine coronary arterial strips. Pre-incubation with 3 micromol/L TAT-MYPT1(1-374), a construct containing the Tat peptide and the residues 1 to 374 of MYPT1, for 15 minutes augmented (2.4-fold) the subsequent contraction induced by adding 1.25 mmol/L of extracellular Ca2+ under 118 mmol/L K+ depolarization, with no augmentation of the [Ca2+]i elevation. The deletion of the Tat peptide, MYPT1(1-374), abolished the augmenting effect. TAT-MYPT1(1-296) demonstrated a weaker but significant augmentation (1.7-fold). However, TAT-MYPT1(1-171), TAT-MYPT1(39-374), TAT-MYPT1(39-296), and TAT-MYPT1(297-374) had no augmenting activity. The myosin light chain phosphorylation level as a function of extracellular Ca2+ concentrations was shifted to the left in the strips pretreated with TAT-MYPT1(1-374) compared with the control. CONCLUSIONS: Region 1 to 296 was the minimal region involved in the enhancement of contraction, and region 297 to 374 played a supplemental role. These results suggested that the interaction mainly between catalytic subunit and MYPT1 play a critical role in the regulation of the endogenous myosin phosphatase in intact smooth muscle.

Actin Cytoskeleton↗
PubMed2004

Endothelium-dependent and independent enhancement of vascular contractility in the ovariectomized rabbit.

OBJECTIVE: Estrogen suppresses contractile response and increases vasodilator response, partly by modulating endothelial function. However, the effect of estrogen on the contractility of vascular smooth muscle remains to be elucidated. We investigated the effect of a long-term estrogen deficiency on vascular contractility and the Ca(2+) sensitivity of the contractile apparatus in arterial smooth muscle. METHODS: Female rabbits were divided into the following three groups: control group, an ovariectomized group (OVX), and a group supplemented with 17beta-estradiol after ovariectomy (OVX+E2). Twelve weeks later, the mesenteric artery was isolated, and the vascular contractility was evaluated. RESULTS: In OVX, the contractile responses to phenylephrine and 118 mM potassium were enhanced, and the basal release of nitric oxide decreased in the strips with endothelium compared with either OVX+E2 or control. An enhancement of contraction was also observed in the strips without endothelium. However, the extent of enhancement was smaller than that observed in the presence of endothelium. The simultaneous measurement of calcium ([Ca(2+)](i)) and tension revealed no significant difference in the [Ca(2+)](i) elevations induced by phenylephrine among the three groups. In the alpha-toxin permeabilized strips, the Ca(2+)-tension relationships obtained both with and without phenylephrine and guanosine triphosphate were similar among the three groups. No difference in the myosin expression and the histology of vascular tissue was observed among the three groups. CONCLUSION: Long-term estrogen deficiency increased the vascular tone mainly by enhancing smooth muscle contractility. Endothelial dysfunction is considered to play a minor role in the augmentation of vascular tone.

Animals↗
PubMed2004

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.

Aged↗
PubMed2004

Regulation of myosin phosphorylation and myofilament Ca2+ sensitivity in vascular smooth muscle.

The Ca2+-dependent, reversible phosphorylation of the 20 kDa regulatory myosin light chain (MLC) plays a primary role in regulating the contraction of smooth muscle. However, it is well known that the Ca2+ signal is not the only factor which regulates such contraction, however, the alteration of the Ca2+ sensitivity in the contractile apparatus is also known to play an important role. The degree of MLC phosphorylation is determined by the balance of the activity between phosphorylation and dephosphorylation. Either the Ca2+-independent activation of MLC phosphorylation or the inhibition of MLC dephosphorylation causes a greater MLC phosphorylation for a given level of Ca2+ signal and thereby potentiates the myofilament Ca2+ sensitivity. The smooth muscle myosin light chain phosphatase (MLCP) consisting of three subunits was first isolated and cloned in the early '90s. The intensive investigation thereafter has uncovered the biochemical basis for regulating the activity of MLCP. The regulation of the MLCP activity is now considered to play a critical role in regulating the myofilament Ca2+ sensitivity. There are three major mechanisms in the regulation of MLCP; (1) the phosphorylation of a 110 kDa regulatory subunit of MLCP (2) the conformational change of the trimeric structure, and (3) the inhibition by a smooth muscle specific inhibitor protein, CPI-17. Furthermore, some kinases have been found to phosphorylate the MLC and activate the contraction of smooth muscle in a Ca2+-independent manner. Numerous protein kinases have been found to be involved in the regulation of MLC phosphorylation, and rho-kinase is one of the most frequently investigated kinases. The smooth muscle physiology is now asked to integrate the current understanding of the biochemical mechanisms and to clarify which kinases and/or proteins in the contractile apparatus play a physiological role in regulating the myofilament Ca2+ sensitivity and how such extracellular contractile stimulation modulates these mechanisms.

Actin Cytoskeleton↗
PubMed2003

Rho-kinase inhibitor inhibits both myosin phosphorylation-dependent and -independent enhancement of myofilament Ca2+ sensitivity in the bovine middle cerebral artery.

The role of Rho kinase in Ca2+ sensitization of the contractile apparatus in smooth muscle was investigated in the bovine middle cerebral artery. U46619, a thromboxane A2 analog, induced a greater sustained contraction with a smaller [Ca2+]i elevation than that seen with 118 mm K+. The level of myosin light chain (MLC) phosphorylation obtained in the initial phase of the contraction was higher than that seen with 118 mm K+; thereafter, it gradually declined to a comparable level in the late phase. During the steady state of the U46619-induced contraction, Y27632 (10 microM), a Rho-kinase inhibitor, partially inhibited [Ca2+]i, although it substantially inhibited tension and MLC phosphorylation. Wortmannin (10 microM), an MLC kinase inhibitor, had no significant effect on [Ca2+]i, but it completely inhibited MLC phosphorylation and partially inhibited tension. The wortmannin-resistant tension development was thus not associated with MLC phosphorylation, and this component was completely inhibited by Y27632. In conclusion, U46619 enhanced Ca2+ sensitivity in a manner both dependent and independent of MLC phosphorylation in the bovine middle cerebral artery. Both mechanisms of Ca2+ sensitization can be inhibited by the Rho-kinase inhibitor.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗