title: GTP requirement for inositol-1,4,5-trisphosphate-induced Ca2+ release from sarcoplasmic reticulum in smooth muscle.
abstract: We have examined inositol-1,4,5-trisphosphate (IP3)-induced Ca2+ release from the sarcoplasmic reticulum (SR) in the skinned vascular smooth muscle. The amount of Ca2+ in the SR was estimated indirectly by caffeine-induced contraction of the skinned preparation. The Ca2+ release from the SR by IP3 required GTP. A non-hydrolyzable analogue of GTP, guanosine 5'-(beta gamma-imido) triphosphate (GppNHp) could substitute for GTP in the IP3-induced Ca2+ release. These results suggest an involvement of GTP-binding protein in the mechanism of Ca2+ release from the SR by IP3 in smooth muscle.
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000494:pharmacology*; D007537:Isometric Contraction; D007700:Kinetics; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D013403:Sugar Phosphates / Q000494:pharmacology*
chemical_list: D007295:Inositol Phosphates; D013403:Sugar Phosphates; D006165:Guanylyl Imidodiphosphate; D002110:Caffeine; D015544:Inositol 1,4,5-Trisphosphate; D006160:Guanosine Triphosphate; D002118:Calcium