Upregulation of Rho-kinase (ROCK-2) expression and enhanced contraction to endothelin-1 in the mesenteric artery from lipopolysaccharide-treated rats.
Effects of bacterial lipopolysaccharide (Escherichia coli serotype, 055:B5, 20 mg kg(-1), i.p., for 6 h) and a Rho-kinase inhibitor, (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl) cyclohexanecarboxamide dihydrochloride monohydrate, Y-27632 (10(-9)-10(-5) M) were investigated on the contractile responses of the rat mesenteric artery to phenylephrine (10(-9)-3 x 10(-5) M), angiotensin-2 (10(-10)-10(-6) M) and endothelin-1 (10(-10)-10(-7) M). Moreover, alteration in the level of Rho-kinase (ROCK-2) expression was examined in the superior mesenteric artery obtained from saline- and lipopolysaccharide-treated rats by Western blotting. Endotoxemic rat mesenteric rings exhibited no different contractions to phenylephrine and angiotensin-2 but augmented contractile activity to endothelin-1. In the mesenteric artery obtained from the endotoxemic rats, acetylcholine-induced vasorelaxation did not differ; pD2 value for acetylcholine was 7.85+/-0.12 in the endotoxemic rings; however, it was 7.81+/-0.15 in the control rings (P>0.05). Y-27632 induced relaxation, which was the same in the control arteries as in endotoxemic ones when contracting agent was phenylephrine. However, when endothelin-1 was used to precontract the rings, Y-27632 produced enhanced relaxation in endotoxemic vessels. pD2 values for Y-27632 were, respectively, 7.69+/-0.12 and 8.20+/-0.10 in control and endotoxemic rings precontracted by endothelin-1 (10(-8) M) (P<0.01). Moreover, Y-27632 (10(-5) M) suppressed the contraction induced by angiotensin-2 (10(-10)-10(-6) M). Western blot analysis revealed that Rho-kinase was upregulated significantly in the mesenteric artery obtained from the rats treated with LPS for 6 h. In addition, serum NO2-/NO3- level, which was detected by Griess method, was 10.0+/-1.4 microM in endotoxemic rats; however, it was 6.6+/-0.5 microM in control (P<0.05). Taken together, these results show that the expression of the contractile protein Rho-kinase could be upregulated in endotoxemic mesenteric artery and this upregulation may be coincided with an enhanced contraction to endothelin-1 but not phenylephrine and angiotensin-2.
Büyükafşar
Kansu
K
Department of Pharmacology Medical Faculty Mersin University Campus Yenişehir 33169 Mersin, Turkey. kbuyukafsar@mersin.edu.tr
Arikan
Onur
O
Ark
Mustafa
M
Kubat
Havva
H
Ozveren
Elif
E
D000109:Acetylcholine / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D009566:Nitrates / Q000097:blood; D009573:Nitrites / Q000097:blood; D010656:Phenylephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology; D054460:rho-Associated Kinases
D000577:Amides; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D009566:Nitrates; D009573:Nitrites; D011725:Pyridines; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D000804:Angiotensin II; C108830:Y 27632; D010656:Phenylephrine; D012965:Sodium Chloride; D011189:Potassium Chloride; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D000109:Acetylcholine