title: Doxorubicin induces calcium release from terminal cisternae of skeletal muscle. A study on isolated sarcoplasmic reticulum and chemically skinned fibers.
abstract: In this study, we investigated the effect of the anticancer drug doxorubicin on Ca2+ fluxes of isolated highly purified sarcoplasmic reticulum fractions (longitudinal tubules and terminal cisternae (Saito, A., Seiler, S., Chu, A., and Fleischer, S. (1984) J. Cell Biol. 99, 875-885] and of chemically skinned skeletal muscle fibers of the rabbit. In terminal cisternae, doxorubicin inhibits Ca2+ uptake (IC50 at 0.5 microM) and increases 2.6-fold Ca2+-dependent ATPase rate (half-maximal activation at 3 microM) and unidirectional Ca2+ efflux (8-fold stimulation at 25 microM). On the contrary, doxorubicin is without effect on longitudinal tubules. In skinned muscle fibers, doxorubicin induces rapid and transient Ca2+ release, as measured by tension development (half-maximal stimulation at 6 microM), which is completely and reversibly inhibited by ruthenium red, a known inhibitor of Ca2+ release from isolated terminal cisternae. Doxorubicin has no effect on the sarcoplasmic reticulum Ca2+ pump and on the contractile apparatus of skinned muscle fibers. It is concluded that doxorubicin activates Ca2+ release from sarcoplasmic reticulum and opens a Ca2+ efflux pathway (Ca2+ channel) selectively localized in terminal cisternae. Doxorubicin might interact with Ca2+ channels involved in physiological Ca2+ release.
authors.forename: F
authors.initials: F
authors.lastname: Zorzato
authors.forename: G
authors.initials: G
authors.lastname: Salviati
authors.forename: T
authors.initials: T
authors.lastname: Facchinetti
authors.forename: P
authors.initials: P
authors.lastname: Volpe
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D004317:Doxorubicin / Q000494:pharmacology*; D007537:Isometric Contraction / Q000187:drug effects; D007700:Kinetics; D008297:Male; D009132:Muscles / Q000378:metabolism* / Q000502:physiology; D011817:Rabbits; D012430:Ruthenium Red / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D012430:Ruthenium Red; D000001:Calcimycin; D002110:Caffeine; D004317:Doxorubicin; D000252:Calcium-Transporting ATPases; D002122:Calcium Chloride; D002118:Calcium