Differential skinning of smooth muscle: a new approach to excitation-contraction coupling.
In intact smooth muscle, the calcium sensitivity of force may increase as well as decrease. Using differently skinned smooth muscle preparations, two pathways involved in the change of calcium sensitivity of force have been identified: in microarteries skinned with beta-escin, GTP (possibly via a G protein) is involved in sensitization to Ca2+, while in porcine coronary arteries skinned with Triton X-100 cyclic AMP and possibly cyclic GMP are involved in desensitization. In both cases, there is a corresponding change in the phosphorylation of the regulatory light chain of myosin, suggesting that the balance of phosphorylating to dephosphorylating reactions is altered at constant [Ca2+].
Pfitzer
G
G
Department of Physiology II, University of Heidelberg, FRG.
Boels
P J
PJ
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability; D000242:Cyclic AMP / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology; D004928:Escin; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000502:physiology; D006168:Guinea Pigs; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D009218:Myosins / Q000378:metabolism; D017830:Octoxynol; D010766:Phosphorylation; D011092:Polyethylene Glycols; D012503:Saponins; D013552:Swine
D012503:Saponins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D011092:Polyethylene Glycols; D004928:Escin; D006160:Guanosine Triphosphate; D017830:Octoxynol; D000242:Cyclic AMP; D009219:Myosin-Light-Chain Kinase; D009218:Myosins; D006152:Cyclic GMP; D002118:Calcium