QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) All Versions of this Article: jpet.105.100040v1 317/2/791    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Budzyn, K. Articles by Sobey, C. G. Search for Related Content PubMed PubMed Citation Articles by Budzyn, K. Articles by Sobey, C. G.

CARDIOVASCULAR

Segmental Differences in the Roles of Rho-Kinase and Protein Kinase C in Mediating Vasoconstriction

Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia

Received December 15, 2005; accepted January 30, 2006.

	Abstract

Top Abstract Materials and Methods Results Discussion References

 
Rho-kinase and protein kinase C (PKC) have each been reported to mediate vasoconstriction via calcium sensitization. However, the relative contributions of these two kinases to vascular contraction, and whether their roles vary between large and small arteries, are largely unknown. We therefore assessed the relative roles of rho-kinase and PKC in mediating vasoconstriction in arteries from three segments of the aortic and mesenteric vasculature. We studied contractile responses of rat isolated thoracic aorta (diameter 2 mm), superior mesenteric artery (SMA; 1.5 mm), and second order branches of the superior mesenteric artery (BMA; 300 µm). The roles of rho-kinase and PKC in mediating contractile responses to phenylephrine, 9,11-dideoxy-9,11-methanoepoxy prostaglandin F₂ (U46619 [GenBank] ), and KCl were assessed by using the rho-kinase inhibitor R-[+]-trans-N-[4-pyridyl]-4-[1-aminoethyl]-cycloheaxanecarboxamide (Y-27632) (1 and 10 µM) and the PKC inhibitor 3-[1-[3-(amidinothio)propyl-1H-indol-3-yl]-3-(1-methyl-1H-indol-3-yl) maleimide (Ro 31-8220) (5 µM). Contractile responses of aorta and SMA were reduced by either 1 or 10 µM Y-27632 (P < 0.05), whereas responses of BMA were reduced by 10 µM (P < 0.05) but not 1 µM Y-27632. In contrast, Ro 31-8220 partly reduced contractile responses in aorta and SMA (P < 0.05), but it abolished responses of BMA (P < 0.05). Cotreatment with Y-27632 and Ro 31-8220 markedly attenuated contractile responses to phenylephrine and KCl in all vessels, but it had only a moderate inhibitory effect on responses to U46619 [GenBank] in aorta and SMA. Thus, contractile responses of the larger arteries can involve both rho-kinase and PKC to varying degrees. Conversely, contractile responses of small mesenteric resistance arteries seem to be mediated exclusively by PKC, with no apparent role for rho-kinase.

MLCP inhibition enhances the sensitivity of the VSM contractile apparatus to [Ca²⁺] and is therefore known as "Ca²⁺ sensitization". The small G protein rho (particularly its rhoA isoform) and its downstream effector rho-kinase have been reported to induce VSM contraction via Ca²⁺ sensitization (Somlyo and Somlyo, 2003; Budzyn et al., 2006). RhoA can be activated after stimulation of heterotrimeric G protein-coupled receptors in response to agonists such as phenylephrine and thrombin (Gong et al., 1997; Seasholtz et al., 1999). In its activated form, rhoA can interact with and activate rho-kinase, which then phosphorylates and inactivates MLCP on its myosin-binding subunit. This leads to an increased proportion of MLC in its phosphorylated state, promoting VSM contraction (Budzyn et al., 2006).

Another mechanism by which Ca²⁺ sensitization can occur is via activation of protein kinase C (PKC). PKC can be activated physiologically by endogenous diacylglycerol or pharmacologically by phorbol esters (Akopov et al., 1998; Chrissobolis and Sobey, 2002). More recently, it has been demonstrated that pathologically important mediators such as oxyhemoglobin and endothelin-1 can also activate PKC (Wickman et al., 2003; McNair et al., 2004). PKC can mediate Ca²⁺ sensitization by phosphorylating the phosphoprotein CPI-17 (Kitazawa et al., 2000), yet this phosphorylation has also been reported to occur via rho-kinase (Koyama et al., 2000). Phosphorylated CPI-17 is a potent inhibitor of MLCP, causing physical dissociation of MLCP subunits, rendering it inactive and therefore promoting increased vascular tone.

Although the influence of PKC on vascular tone has been investigated in various vascular beds, studies have thus far yielded conflicting results with regard to the physiological significance of this pathway (Kadokami et al., 1996; Chrissobolis and Sobey, 2001; Woodsome et al., 2001). Furthermore, the relative contributions of rho-kinase and PKC to vascular contraction and whether their roles vary between large and small blood vessels within a vascular bed are not well understood. This study has therefore investigated the relative roles of rho-kinase and PKC in mediating contraction of aorta and small mesenteric arteries and whether there are segmental differences in these roles.

	Materials and Methods

Top Abstract Materials and Methods Results Discussion References

 
All experimental procedures were approved by the University of Melbourne Animal Experimentation Ethics Committee and complied with National Health and Medical Research Council of Australia guidelines. Adult male Sprague-Dawley rats (237-500 g; n = 97) were studied.

Experimental Protocol. Rats were euthanized by inhalation of 80% CO₂, 20% O₂ and decapitation. Thoracic aorta (diameter 2 mm), superior mesenteric artery (SMA; 1.5 mm), or second order branches of the superior mesenteric artery (BMA; 300 µm) were isolated, cleaned, and cut into segments of equal length. Aortic segments were mounted at 0.5 g in 10-ml organ chambers containing Krebs-bicarbonate solution bubbled with 5% CO₂ in O₂ at 37°C. Tension was continuously recorded using a Grass FT03 force transducer (Grass Instruments, Quincy, MA) and MacLab4 Chart version 3.5.4 computer software (AD Instruments, Colorado Springs, CO). SMA and BMA segments were mounted at 5 mN in 5-ml chambers of a small vessel myograph (model 610M Multi Myograph; Danish Myo Technology, Aarhus, Denmark) containing Krebs-bicarbonate solution bubbled with 5% CO₂ in O₂ at 37°C. Tension was continuously recorded on a chart recorder (model 3721; Yokogawa, Tokyo, Japan).

After equilibration for 45 min, arterial segments were exposed to an isotonic high K⁺-containing physiological saline solution (KPSS; [K⁺]_KPSS = 124 mM). KPSS-induced contraction reached a stable level over 10 to 20 min. After washout and return to stable baseline, segments were precontracted to 50% of their KPSS response with serotonin (1-10 µM). Sustained relaxation (>70% of precontracted tone) in response to 10 µM acetylcholine confirmed the presence of functional endothelium. In some experiments, endothelium of BMA was removed by gentle rubbing with a human hair. After washout and return to stable baseline, cumulative concentration-response curves were established to the ₁-adrenoceptor agonist phenylephrine, the thromboxane A₂ mimetic U46619 [GenBank] , and the receptor-independent depolarizing agent KCl. Two to three such curves were typically performed per arterial segment. The order in which agonists were applied was randomized and did not affect the responses obtained. All control data were obtained in rings not previously exposed to any inhibitor.

Effects of Rho-Kinase and PKC Inhibition on Vascular Contraction. The effect of the rho-kinase inhibitor Y-27632 (1 or 10 µM) on contractile responses was assessed by treating arterial segments for 30 min before commencing cumulative additions of phenylephrine, U46619 [GenBank] , or KCl. Likewise, the effect of the PKC inhibitor Ro 31-8220 (5 µM) on contractile responses was assessed by 30-min treatment before the addition of contractile agents. In some experiments, the effects of combined Y-27632 (1 µM) and Ro 31-8220 (5 µM) treatment on responses to contractile agents were also studied. The effect of rho-kinase or PKC inhibition on contractions to the PKC activator phorbol 12,13-dibutyrate (PdB; 0.1 µM) was also investigated.

Drugs. Y-27632 was obtained from Welfide Corporation (Osaka, Japan). Ro 31-8220 was obtained from Calbiochem (San Diego, CA). All other drugs were obtained from Sigma-Aldrich (St. Louis, MO). Ro 31-8220 was dissolved as a stock solution of 1 mM in 100% dimethyl sulfoxide and diluted in deionized water. All other drugs were dissolved and diluted in deionized water.

Analyses and Statistics. All responses to contractile agents are presented as percentage of the KPSS response of each arterial segment. Each n represents the number of animals used. Statistical analysis was carried out using one-way analysis of variance followed by Dunnett's or Tukey's post hoc tests, as appropriate. P < 0.05 was considered statistically significant.

	Results

Top Abstract Materials and Methods Results Discussion References

 
Effect of Rho-Kinase Inhibition on Contractile Responses to Phenylephrine and PdB. In aorta, contractile responses to phenylephrine were effectively abolished by either 1 or 10 µM Y-27632 (P < 0.05; Fig. 1a). Contractile responses of SMA were also reduced by 1 µM Y-27632 albeit to a lesser degree and very nearly abolished by 10 µM Y-27632 (P < 0.05; Fig. 1c). Furthermore, although contractile responses of BMA were unaffected by 1 µM Y-27632, these responses were markedly attenuated by 10 µM Y-27632 (P < 0.05; Fig. 1e). In each artery, maximum contractile responses to 0.1 µM PdB were abolished by 5 µM Ro 31-8220, but they were unaffected by 1 µM Y-27632 (Fig. 1, b, d, and f). Conversely, contractile responses of all arteries to PdB were profoundly inhibited by 10 µM Y-27632 (P < 0.05; Fig. 1, b, d, and f).

View larger version (28K): [in this window] [in a new window]   Fig. 1. Effects of rho-kinase inhibition on contractile responses to phenylephrine and PdB. Concentration-response curves of aorta (a), SMA (c), and BMA (e) to phenylephrine in the presence of vehicle or Y-27632 (1 or 10 µM). Contractile responses of aorta (b), SMA (d), and BMA (f) to PdB (0.1 µM) in the presence of vehicle, Y-27632 (Y; 1 or 10 µM), or Ro 31-8220 (Ro; 5 µM). All values are mean ± S.E., n = 4 to 15. *, P < 0.05 versus vehicle maximum.

View larger version (17K): [in this window] [in a new window]   Fig. 2. Effects of rho-kinase and PKC inhibition on contractile responses to phenylephrine. Concentration-response curves of aorta (a), SMA (b), and BMA (c) to phenylephrine in the presence of vehicle (veh), Ro 31-8220 (Ro; 5 µM), or Y-27632 (Y; 1 µM) alone or in combination. All values are mean ± S.E., n = 6 to 8. *, P < 0.05 versus vehicle maximum; , P < 0.05 versus Y-27632 maximum.

View larger version (17K): [in this window] [in a new window]   Fig. 3. Effects of rho-kinase and PKC inhibition on contractile responses to KCl. Concentration-response curves of aorta (a), SMA (b), and BMA (c) to KCl in the presence of vehicle (veh), Ro 31-8220 (Ro; 5 µM), or Y-27632 (Y; 1 µM) alone or in combination. All values are mean ± S.E., n = 3 to 10. *, P < 0.05 versus vehicle maximum; , P < 0.05 versus Y-27632 maximum.

Effect of Rho-Kinase and PKC Inhibition on Contractile Responses to U46619 [GenBank] . Maximum contractile responses to U46619 [GenBank] were unaffected by 1 µM Y-27632 in aorta and BMA (Fig. 4, a and c), whereas responses of SMA were slightly attenuated (P < 0.05; Fig. 4b). Ro 31-8220 reduced contractile responses of SMA and abolished responses of BMA (P < 0.05; Fig. 4, b and c), but it had no effect in aorta (Fig. 4a). Furthermore, although U46619 [GenBank] -induced contractile responses were also abolished in BMA during cotreatment with Y-27632 and Ro 31-8220 (P < 0.05; Fig. 4c), these inhibitors had a comparatively modest effect in aorta and SMA (P < 0.05; Fig. 4, a and b).

View larger version (17K): [in this window] [in a new window]   Fig. 4. Effects of rho-kinase and PKC inhibition on contractile responses to U46619 [GenBank] . Concentration-response curves of aorta (a), SMA (b), and BMA (c) to U46619 [GenBank] in the presence of vehicle (veh), Ro 31-8220 (Ro; 5 µM), or Y-27632 (Y; 1 µM) alone or in combination. All values are mean ± S.E., n = 3 to 10. *, P < 0.05 versus vehicle maximum; , P < 0.05 versus Y-27632 maximum.

	Discussion

Top Abstract Materials and Methods Results Discussion References

Role of Rho-Kinase in Vascular Contraction. The role of rho-kinase in mediating contractile responses has been studied extensively (Bolz et al., 2000; Matrougui et al., 2001; Budzyn et al., 2006; Faraci et al., 2006). However, to the best of our knowledge, only one previous study has compared how the contribution of rho-kinase to contractile responses might vary between functionally distinct arteries within a vascular bed (Asano and Nomura, 2003). We found evidence for a role of rho-kinase in contractile responses to phenylephrine in both aorta and SMA, albeit to varying degrees. For example, responses of the aorta to phenylephrine were effectively abolished by rho-kinase inhibition, as we have demonstrated previously (Budzyn et al., 2004), as opposed to the relatively modest reduction in SMA. In stark contrast to the aorta, there was no effect of rho-kinase inhibition on phenylephrine-induced contractions of the small BMA. The rho-kinase inhibitor also modestly attenuated KCl-induced contractions in aorta and SMA, but it had no inhibitory effect in the smaller branch arteries. Thus, rho-kinase contributes to these contractile responses to markedly different degrees, according to the segment of the vascular bed. Interestingly, the modest attenuation of responses to KCl in the larger vessels, suggests a minor role for rho-kinase in the contractile response to this non-G protein-coupled receptor agonist, consistent with recent findings (Ratz et al., 2005).

Rho-kinase inhibition caused relatively weak attenuation of contractile responses to the thromboxane A₂ mimetic U46619 [GenBank] , in aorta and SMA. Thus, rho-kinase seems to play only a minor role in mediating contractile responses to this agent in these larger arteries. Previous studies examining the mechanisms of U46619 [GenBank] -induced arterial contraction have reported variable findings with regard to the contribution of rho-kinase (Nobe and Paul, 2001; Tasaki et al., 2003; Wilson et al., 2005). Importantly, rho-kinase inhibition had no effect on contractile responses of BMA to all three contractile agents. Thus, in general, it seems that rho-kinase has a major role in mediating contractile responses of larger conductance vessels, whereas its contribution is greatly diminished in small resistance vessels (Asano and Nomura, 2003).

Role of PKC in Vascular Contraction. Recent studies using inhibitors with improved selectivity for PKC have yielded conflicting results regarding the physiological importance of that enzyme in the vasculature (Chrissobolis and Sobey, 2001; Shirao et al., 2002; McNair et al., 2004). Furthermore, little is known as to whether there are segmental differences in the role of PKC in vasoconstriction. We found evidence that PKC can contribute to contractile responses independently of rho-kinase, in each artery studied, albeit to varying degrees. For example, PKC inhibition with Ro 31-8220 had a more marked inhibitory effect on responses to phenylephrine and KCl in SMA than aorta, where rho-kinase inhibition was highly effective. Remarkably, Ro 31-8220 abolished responses of BMA to all contractile agents studied. However, contractile responses to U46619 [GenBank] were unaffected by PKC inhibition in aorta but significantly attenuated in SMA. Our finding that PKC had little apparent role in U46619 [GenBank] -induced contractions of the aorta contrasts with two recent studies, suggesting that PKC does play a significant role in U46619 [GenBank] -induced contractile responses in rat aorta and pulmonary vessels (Cogolludo et al., 2003; Tasaki et al., 2003). One reason for the different conclusions might be the different pharmacological inhibitors used. The precise roles of PKC in mediating U46619 [GenBank] -induced contractile responses therefore still remain to be more definitively elucidated. Nevertheless, our findings clearly suggest that the importance of PKC in mediating vascular contraction is greater in resistance vessels such as second order branches of the SMA, relative to larger conductance vessels such as aorta where rho-kinase seems to dominate.

Generally, we found that combined rho-kinase and PKC inhibition resulted in near or complete abolition of all contractile responses in each artery studied, suggesting that a combination of these two kinases underlies the predominant mechanism(s) of contraction of perhaps most, if not all, blood vessels. However, although U46619 [GenBank] -induced contractions of aorta or SMA were also attenuated by cotreatment with the two inhibitors, this effect was only modest. It is possible that the inhibitor-insensitive component of the response may actually be Ca²⁺-dependent, as suggested previously (Cogolludo et al., 2003; Tasaki et al., 2003) or might even involve alternative Ca²⁺-sensitizing mechanisms. We also acknowledge that we cannot exclude the possibility of an interaction between the rho-kinase and PKC pathways to induce contraction in the arteries studied. Some recent reports have provided evidence for such an interaction within the coronary and cerebral circulations (Kandabashi et al., 2003; Obara et al., 2005), yet whether the nature of this varies between vascular beds is still unclear.

PKC and Vascular Endothelium. We recently reported that in aorta, where the predominant endothelium-derived relaxing factor is NO, effectiveness of rho-kinase inhibition is much greater in the presence of endothelium and, more specifically, endothelial NO synthase activity (Budzyn et al., 2005). This observation is consistent with the concept that there are several levels of interaction between rho-kinase and endothelial NO (Takemoto et al., 2002; Budzyn et al., 2004; Wolfrum et al., 2004). In contrast to conductance arteries, in resistance arteries such as BMA, the predominant endothelium-derived relaxing agent is thought to be endothelium-derived hyperpolarizing factor (EDHF) rather than NO (Vanhoutte, 2004). We therefore tested whether, like rho-kinase and NO in aorta, PKC and EDHF can interact within the small BMA such that the effectiveness of Ro 31-8220 might be attenuated by endothelial removal. However, the dramatic effect of PKC inhibition on contractile responses of BMA was found to be unaffected by removal of endothelium, suggesting that EDHF is unlikely to modulate PKC-mediated contractile responses of this small artery.

Selectivity of Y-27632. Several of the present interpretations concerning the functional roles of rho-kinase rely on the selectivity of the pharmacological inhibitor Y-27632. Experimentally, Y-27632 has been used extensively to characterize both the physiological and pathophysiological roles of rho-kinase (Uehata et al., 1997; Chrissobolis and Sobey, 2001; Didion et al., 2005), and this agent is generally considered to be a highly selective rho-kinase inhibitor. We sought to test for potential nonspecific effects of Y-27632 on PKC by assessing its effect on contractile responses to the potent PKC activator PdB. Responses to PdB were abolished by Ro 31-8220, confirming that the PdB-induced contraction is entirely dependent on PKC activity. Interestingly, however, 10 µM but not 1 µM Y-27632 markedly inhibited responses to PdB. We interpret these data as indicating that at a concentration of 1 µM, the inhibitory effects of Y-27632 on vasoconstriction are probably due to selective inhibition of rho-kinase alone. However, at 10 µM (or higher concentrations), Y-27632 exerts nonspecific inhibitory effects on PKC-mediated vascular responses. Our results are in agreement with those of another study reporting that 10 µM Y-27632 inhibited phorbol ester-induced arterial contractions, in parallel with direct inhibition of PKC (Eto et al., 2001). Thus, past conclusions concerning the role of rho-kinase based on effects of 10 µMor higher of Y-27632 might warrant reevaluation.

Selectivity of Ro 31-8220. Unlike staurosporine and sphingosine, Ro 31-8220 is regarded as a relatively selective PKC inhibitor at the concentration used in the present study (5 µM), but it is not isoform-selective. It does, however, inhibit "conventional" PKC isoforms (, , and ) more potently than "atypical" PKC isoforms ( and ) (Davies et al., 2000). Eleven isoforms of PKC have been identified, and importantly, several of these are expressed in the VSM of the arteries studied (Salamanca and Khalil, 2005). Therefore, to elucidate precisely which PKC isoforms mediate the contractile effects in the arteries studied, further studies using isoform-specific inhibitors or antibodies might be warranted.

In summary, the present results provide strong functional evidence for rho-kinase and PKC having additive, yet differential roles in contractile responses of segmentally distinct arteries within a vascular bed. Furthermore, these roles may vary according to the contractile stimulus. We speculate that alterations to these signaling pathways during disease states may lead to diverse functional consequences depending on the vascular segment.

	Footnotes

 
These studies were supported by Project Grant ID 208969 from the National Health and Medical Research Council of Australia (NHMRC). C.G.S. is a Senior Research Fellow and P.D.M. is a Principal Research Fellow of the NHMRC. K.B. is supported by a Melbourne University Research Scholarship.

Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.

doi:10.1124/jpet.105.100040.

ABBREVIATIONS: VSM, vascular smooth muscle; MLC, myosin light chain; MLCK, myosin light chain kinase; MLCP, myosin light chain phosphatase; PKC, protein kinase C; SMA, superior mesenteric artery; BMA, second order branches of superior mesenteric artery; KPSS, high K⁺-containing physiological saline solution; U46619 [GenBank] , 9,11-dideoxy-9,11-methanoepoxy prostaglandin F₂; Y-27632, R-[+]-trans-N-[4-pyridyl]-4-[1-aminoethyl]-cycloheaxanecarboxamide; Ro 31-8220, 3-[1-[3-(amidinothio)propyl-1H-indol-3-yl]-3-(1-methyl-1H-indol-3-yl) maleimide; PdB, phorbol 12,13-dibutyrate; EDHF, endothelium-derived hyperpolarizing factor.

¹ Current affiliation: Department of Pharmacology, Monash University, Clayton, VIC, Australia.

Address correspondence to: Dr. Christopher G. Sobey, Department of Pharmacology, Monash University, Clayton, Victoria 3800, Australia. E-mail: chris.sobey{at}med.monash.edu.au

	References

Top Abstract Materials and Methods Results Discussion References

 

Akopov SE, Zhang L, and Pearce WJ (1998) Regulation of Ca²⁺ sensitization by PKC and rho proteins in ovine cerebral arteries: effects of artery size and age. Am J Physiol 275: H930-H939.

Asano M and Nomura Y (2003) Comparison of inhibitory effects of Y-27632, a rho kinase inhibitor, in strips of small and large mesenteric arteries from spontaneously hypertensive and normotensive Wistar-Kyoto rats. Hypertens Res 26: 97-106.[CrossRef][Medline]

Bolz SS, Galle J, Derwand R, de Wit C, and Pohl U (2000) Oxidized LDL increases the sensitivity of the contractile apparatus in isolated resistance arteries for Ca²⁺ via a rho- and rho kinase-dependent mechanism. Circulation 102: 2402-2410.[Abstract/Free Full Text]

Budzyn K, Marley PD, and Sobey CG (2004) Chronic mevastatin modulates receptor-dependent vascular contraction in eNOS-deficient mice. Am J Physiol 287: R342-R348.

Budzyn K, Marley PD, and Sobey CG (2005) Opposing roles of endothelial and smooth muscle phosphatidylinositol 3-kinase in vasoconstriction: effects of rho-kinase and hypertension. J Pharmacol Exp Ther 313: 1248-1253.[Abstract/Free Full Text]

Budzyn K, Marley PD, and Sobey CG (2006) Targeting rho and rho-kinase in the treatment of cardiovascular disease. Trends Pharmacol Sci 27: 97-104.[CrossRef][Medline]

Chrissobolis S and Sobey CG (2001) Evidence that rho-kinase activity contributes to cerebral vascular tone in vivo and is enhanced during chronic hypertension: comparison with protein kinase C. Circ Res 88: 774-779.[Abstract/Free Full Text]

Chrissobolis S and Sobey CG (2002) Inhibitory effects of protein kinase C on inwardly rectifying K⁺- and ATP-sensitive K⁺ channel-mediated responses of the basilar artery. Stroke 33: 1692-1697.[Abstract/Free Full Text]

Cogolludo A, Moreno L, Bosca L, Tamargo J, and Perez-Vizcaino F (2003) Thromboxane A₂-induced inhibition of voltage-gated K⁺ channels and pulmonary vasoconstriction: role of protein kinase Czeta. Circ Res 93: 656-663.[Abstract/Free Full Text]

Davies SP, Reddy H, Caivano M, and Cohen P (2000) Specificity and mechanism of action of some commonly used protein kinase inhibitors. Biochem J 351: 95-105.[CrossRef][Medline]

Didion SP, Lynch CM, Baumbach GL, and Faraci FM (2005) Impaired endothelium-dependent responses and enhanced influence of rho-kinase in cerebral arterioles in type II diabetes. Stroke 36: 342-347.[Abstract/Free Full Text]

Eto M, Kitazawa T, Yazawa M, Mukai H, Ono Y, and Brautigan DL (2001) Histamine-induced vasoconstriction involves phosphorylation of a specific inhibitor protein for myosin phosphatase by protein kinase C alpha and delta isoforms. J Biol Chem 276: 29072-29078.[Abstract/Free Full Text]

Faraci FM, Lamping KG, Modrick ML, Ryan MJ, Sigmund CD, and Didion SP (2006) Cerebral vascular effects of angiotensin II: new insights from genetic models. J Cereb Blood Flow Metab 25, in press.

Gong MC, Fujihara H, Somlyo AV, and Somlyo AP (1997) Translocation of rhoA associated with Ca²⁺ sensitization of smooth muscle. J Biol Chem 272: 10704-10709.[Abstract/Free Full Text]

Kadokami T, Shimokawa H, Fukumoto Y, Ito A, Takayanagi T, Egashira K, and Takeshita A (1996) Coronary artery spasm does not depend on the intracellular calcium store but is substantially mediated by the protein kinase C-mediated pathway in a swine model with interleukin-1b in vivo. Circulation 94: 190-196.[Abstract/Free Full Text]

Kandabashi T, Shimokawa H, Miyata K, Kunihiro I, Eto Y, Morishige K, Matsumoto Y, Obara K, Nakayama K, Takahashi S, et al. (2003) Evidence for protein kinase C-mediated activation of rho-kinase in a porcine model of coronary artery spasm. Arterioscler Thromb Vasc Biol 23: 2209-2214.[Abstract/Free Full Text]

Kitazawa T, Eto M, Woodsome TP, and Brautigan DL (2000) Agonists trigger G protein-mediated activation of the CPI-17 inhibitor phosphoprotein of myosin light chain phosphatase to enhance vascular smooth muscle contractility. J Biol Chem 275: 9897-9900.[Abstract/Free Full Text]

Koyama M, Ito M, Feng J, Seko T, Shiraki K, Takase K, Hartshorne DJ, and Nakano T (2000) Phosphorylation of CPI-17, an inhibitory phosphoprotein of smooth muscle myosin phosphatase, by Rho-kinase. FEBS Lett 475: 197-200.[CrossRef][Medline]

Matrougui K, Tanko LB, Loufrani L, Gorny D, Levy BI, Tedgui A, and Henrion D (2001) Involvement of Rho-kinase and the actin filament network in angiotensin II-induced contraction and extracellular signal-regulated kinase activity in intact rat mesenteric resistance arteries. Arterioscler Thromb Vasc Biol 21: 1288-1293.[Abstract/Free Full Text]

McNair LL, Salamanca DA, and Khalil RA (2004) Endothelin-1 promotes Ca²⁺ antagonist-insensitive coronary smooth muscle contraction via activation of epsilon-protein kinase C. Hypertension 43: 897-904.[Abstract/Free Full Text]

Nobe K and Paul RJ (2001) Distinct pathways of Ca²⁺ sensitization in porcine coronary artery: effects of rho-related kinase and protein kinase C inhibition on force and intracellular Ca²⁺. Circ Res 88: 1283-1290.[Abstract/Free Full Text]

Obara K, Nishizawa S, Koide M, Nozawa K, Mitate A, Ishikawa T, and Nakayama K (2005) Interactive role of protein kinase C-delta with rho-kinase in the development of cerebral vasospasm in a canine two-hemorrhage model. J Vasc Res 42: 67-76.[CrossRef][Medline]

Ratz PH, Berg KM, Urban NH, and Miner AS (2005) Regulation of smooth muscle calcium sensitivity: KCl as a calcium-sensitizing stimulus. Am J Physiol 288: C769-C783.

Salamanca DA and Khalil RA (2005) Protein kinase C isoforms as specific targets for modulation of vascular smooth muscle function in hypertension. Biochem Pharmacol 70: 1537-1547.[CrossRef][Medline]

Seasholtz TM, Majumdar M, Kaplan DD, and Heller Brown J (1999) Rho and rho kinase mediate thrombin-stimulated vascular smooth muscle cell DNA synthesis and migration. Circ Res 84: 1186-1193.[Abstract/Free Full Text]

Shirao S, Kashiwagi S, Sato M, Miwa S, Nakao F, Kurokawa T, Todoroki-Ikeda N, Mogami K, Mizukami Y, Kuriyama S, et al. (2002) Sphingosylphosphorylcholine is a novel messenger for rho-kinase-mediated Ca²⁺ sensitization in the bovine cerebral artery: unimportant role for protein kinase C. Circ Res 91: 112-119.[Abstract/Free Full Text]

Somlyo AP and Somlyo AV (2000) Signal transduction by G-proteins, rho-kinase and protein phosphatase to smooth muscle and non-muscle myosin II. J Physiol (Lond) 522: 177-185.[Abstract/Free Full Text]

Somlyo AP and Somlyo AV (2003) Ca²⁺ sensitivity of smooth muscle and nonmuscle myosin II: modulated by G proteins, kinases, and myosin phosphatase. Physiol Rev 83: 1325-1358.[Abstract/Free Full Text]

Takemoto M, Sun J, Hiroki J, Shimokawa H, and Liao JK (2002) Rho-kinase mediates hypoxia-induced downregulation of endothelial nitric oxide synthase. Circulation 106: 57-62.[Abstract/Free Full Text]

Tasaki K, Hori M, Ozaki H, Karaki H, and Wakabayashi I (2003) Difference in signal transduction mechanisms involved in 5-hydroxytryptamine- and U46619-induced vasoconstrictions. J Smooth Muscle Res 39: 107-117.[CrossRef][Medline]

Uehata M, Ishizaki T, Satoh H, Ono T, Kawahara T, Morishita T, Tamakawa H, Yamagami K, Inui J, Maekawa M, et al. (1997) Calcium sensitization of smooth muscle mediated by a Rho-associated protein kinase in hypertension. Nature (Lond) 389: 990-994.[CrossRef][Medline]

Vanhoutte PM (2004) Endothelium-dependent hyperpolarizations: the history. Pharmacol Res 49: 503-508.[CrossRef][Medline]

Wickman G, Lan C, and Vollrath B (2003) Functional roles of the rho/rho kinase pathway and protein kinase C in the regulation of cerebrovascular constriction mediated by hemoglobin: relevance to subarachnoid hemorrhage and vasospasm. Circ Res 92: 809-816.[Abstract/Free Full Text]

Wilson DP, Susnjar M, Kiss E, Sutherland C, and Walsh MP (2005) Thromboxane A₂-induced contraction of rat caudal arterial smooth muscle involves activation of Ca²⁺ entry and Ca²⁺ sensitization: Rho-associated kinase-mediated phosphorylation of MYPT1 at Thr-855, but not Thr-697. Biochem J 389: 763-774.[CrossRef][Medline]

Wolfrum S, Dendorfer A, Rikitake Y, Stalker TJ, Gong Y, Scalia R, Dominiak P, and Liao JK (2004) Inhibition of Rho-kinase leads to rapid activation of phosphatidylinositol 3-kinase/protein kinase Akt and cardiovascular protection. Arterioscler Thromb Vasc Biol 24: 1842-1847.[Abstract/Free Full Text]

Woodsome TP, Eto M, Everett A, Brautigan DL, and Kitazawa T (2001) Expression of CPI-17 and myosin phosphatase correlates with Ca²⁺ sensitivity of protein kinase C-induced contraction in rabbit smooth muscle. J Physiol (Lond) 535: 553-564.[Abstract/Free Full Text]

This article has been cited by other articles:

				S. Rattan and C. A. Patel Selectivity of ROCK inhibitors in the spontaneously tonic smooth muscle Am J Physiol Gastrointest Liver Physiol, March 1, 2008; 294(3): G687 - G693. [Abstract] [Full Text] [PDF]

				K. J. Allahdadi, L. C. Duling, B. R. Walker, and N. L. Kanagy Eucapnic intermittent hypoxia augments endothelin-1 vasoconstriction in rats: role of PKC{delta} Am J Physiol Heart Circ Physiol, February 1, 2008; 294(2): H920 - H927. [Abstract] [Full Text] [PDF]

				K. J. Allahdadi, B. R. Walker, and N. L. Kanagy ROK contribution to endothelin-mediated contraction in aorta and mesenteric arteries following intermittent hypoxia/hypercapnia in rats Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H2911 - H2918. [Abstract] [Full Text] [PDF]

				S. A. Barman Vasoconstrictor effect of endothelin-1 on hypertensive pulmonary arterial smooth muscle involves Rho-kinase and protein kinase C Am J Physiol Lung Cell Mol Physiol, August 1, 2007; 293(2): L472 - L479. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) All Versions of this Article: jpet.105.100040v1 317/2/791    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Budzyn, K. Articles by Sobey, C. G. Search for Related Content PubMed PubMed Citation Articles by Budzyn, K. Articles by Sobey, C. G.