Smooth muscle myosin phosphatase inhibition and force enhancement by black sponge toxin.
Smooth muscle contraction depends on the state of myosin phosphorylation and hence on the balance of myosin light chain kinase and phosphatase activity. Effects of okadaic acid isolated from black sponge on both enzyme activities and contractility were studied in chemically skinned fibers from guinea pig taenia coli. The toxin strongly inhibits myosin phosphatase and enhances tension development.
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors; D000818:Animals; D004988:Ethers, Cyclic / Q000494:pharmacology*; D006168:Guinea Pigs; D009119:Muscle Contraction / Q000187:drug effects; D009124:Muscle Proteins / Q000037:antagonists & inhibitors*; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology*; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors; D043263:Myosin-Light-Chain Phosphatase; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D010766:Phosphorylation; D013268:Stimulation, Chemical
D004988:Ethers, Cyclic; D009124:Muscle Proteins; D019319:Okadaic Acid; D009219:Myosin-Light-Chain Kinase; D010749:Phosphoprotein Phosphatases; D043263:Myosin-Light-Chain Phosphatase; D015105:3',5'-Cyclic-AMP Phosphodiesterases