title: Comparative pharmacological analysis of Rho-kinase inhibitors and identification of molecular components of Ca2+ sensitization in the rat lower urinary tract.
abstract: We aimed to compare the expression and function of molecular components of the RhoA/Rho-kinase signaling pathway in the contractile responses of detrusor, trigonal and urethral smooth muscle, using selective Rho-kinase inhibitors. Contractility studies and molecular approaches were employed to demonstrate the expression patterns and functional activity of the RhoA/Rho-kinase signaling pathway in the lower urinary tract. Frequency-response curves (1-32 Hz) and concentration-response curves (CRC) to carbachol (CCh, 0.01-30 microM), phenylephrine (PE, 0.01-300 microM) and endothelin-1 (ET-1, 0.01-100 nM) were significantly attenuated (p<0.01) following incubation with the Rho-kinase inhibitors H-1152 (0.1-1 microM), Y-27632 (1-10 microM) or HA-1077 (10 microM). Addition of Rho-kinase inhibitors also markedly reduced (p<0.01) the contractions evoked by either KCl (80 mM) or alpha,beta-methylene ATP (alpha,beta-mATP, 10 microM). Among the Rho-kinase inhibitors tested, H-1152 was approximately 9-16 times more potent than Y-27632 or HA-1077. In addition, basal tone of detrusor and trigonal strips was reduced following addition of Y-27632 (10 microM), H-1152 (1 microM) and HA-1077 (10 microM). The expression of RhoA, RhoGDI, leukemia-associated RhoGEF (LARG) and p115RhoGEF was similar among the detrusor, trigone and urethra, whereas Rho-kinase alpha, Rho-kinase beta and PDZ-RhoGEF protein levels were significantly lower in the urethra. Components of the RhoA/Rho-kinase signaling are expressed in detrusor, trigonal and urethral smooth muscle and dynamically regulate contraction and tone. Manipulation of RhoGEF expression may provide further understanding of mechanisms involving Ca(2+) sensitization in the lower urinary tract.
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, UNICAMP, Campinas, SP, Brazil. cet@fcm.unicamp.br
authors.forename: Cleber E
authors.initials: CE
authors.lastname: Teixeira
authors.forename: Liming
authors.initials: L
authors.lastname: Jin
authors.forename: Fernanda B M
authors.initials: FB
authors.lastname: Priviero
authors.forename: Zhekang
authors.initials: Z
authors.lastname: Ying
authors.forename: R Clinton
authors.initials: RC
authors.lastname: Webb
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D015153:Blotting, Western; D020013:Calcium Signaling / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D019332:Endothelin-1 / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D009543:Nifedipine / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014521:Urethra / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D001743:Urinary Bladder / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D054460:rho-Associated Kinases; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C459092:2-methyl-1-((4-methyl-5-isoquinolinyl)sulfonyl)homopiperazine; D000577:Amides; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D020730:Guanine Nucleotide Dissociation Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D011725:Pyridines; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; C108830:Y 27632; D001285:Atropine; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000255:Adenosine Triphosphate; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein; D009543:Nifedipine; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; C049347:fasudil