Sevoflurane inhibits guanosine 5'-[gamma-thio]triphosphate-stimulated, Rho/Rho-kinase-mediated contraction of isolated rat aortic smooth muscle.
BACKGROUND
The Rho/Rho-kinase signaling pathway plays an important role in mediating Ca2+ sensitization of vascular smooth muscle. The effect of anesthetics on Rho/Rho-kinase-mediated vasoconstriction has not been determined to date. This study is designed to examine the possible inhibitory effects of sevoflurane on the Rho/Rho-kinase pathway by measuring guanosine 5'-[gamma-thio]triphosphate (GTP gamma S)-stimulated contraction and translocation of RhoA (one of the three Rho subtypes) and Rock-2 (one of the two Rho-kinase subtypes) from the cytosol to the membrane in rat aortic smooth muscle.


METHODS
GTP gamma S-induced contraction of rat aortic endothelium-denuded rings was measured using an isometric force transducer, and GTP gamma S-stimulated membrane translocation of RhoA and Rock-2 in smooth muscle cells was detected with Western blotting in the presence and absence of sevoflurane.


RESULTS
GTP gamma S (10(-4) m) induced a sustained contraction, which was significantly inhibited by the Rho-kinase inhibitor, Y27632 (3 x 10(-6) m). Before treatment with GTP gamma S, RhoA and Rock-2 were detected primarily in the cytosolic fraction. GTP gamma S (10(-4) m) stimulated the translocation of RhoA and Rock-2 from the cytosol to the membrane, which was sustained for more than 60 min. Sevoflurane (1.7, 3.4, and 5.1%) concentration dependently inhibited the GTP gamma S-induced constriction of rat aortic smooth muscle with a reduction of constriction of 52-75% (P < 0.01, n = 8), and attenuated the translocation of RhoA and Rock-2 by 31-66% and 34-78%, respectively (P < 0.05-0.01, respectively; n = 4).


CONCLUSIONS
The current findings show that sevoflurane depresses the GTP gamma S-stimulated contraction and translocation of both Rho and Rho-kinase from the cytosol in a concentration-dependent manner, indicating that sevoflurane is able to inhibit vasoconstriction mediated by the Rho/Rho-kinase pathway in rat aortic smooth muscle.
Yu
Jingui
J
Department of Anesthesiology, Wakayama Medical University, Wakayama City, Japan.
Ogawa
Koji
K
Tokinaga
Yasuyuki
Y
Hatano
Yoshio
Y
D000577:Amides / Q000494:pharmacology; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D000077149:Sevoflurane; D015398:Signal Transduction / Q000187:drug effects; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors* / Q000502:physiology*; D054460:rho-Associated Kinases
D000577:Amides; D018685:Anesthetics, Inhalation; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D008738:Methyl Ethers; D009125:Muscle Relaxants, Central; D011725:Pyridines; C108830:Y 27632; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000077149:Sevoflurane; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020741:rho GTP-Binding Proteins