Key result
Cytochalasin-B reversibly disrupts existing myofibrils, inhibits new myofibril formation, and stops heartbeat in cultured 11- to 13-somite chick embryos.
Cytochalasin-B reversibly disrupts myofibril structure and function in early developing chick embryo hearts, demonstrating age-dependent fibrillar sensitivity.
No immediate clinical implications; hypothesis-generating for cytoskeletal roles in cardiac myofibrillogenesis.
Developing cardiac muscle cells of 11- to 13-somite chick embryos are sensitive to cytochalasin-B. In cultured chick embryos, ranging in development from 11 to 13 somites, hearts stop beating in the presence of this agent. Both polarized light and electron microscopic examination show that cytochalasin-B disrupts existing myofibrils and inhibits the formation of new ones. Discrete Z-bands are not present in treated heart cells and thick, presumably myosin, filaments are found in disarray. These effects are reversible; after cytochalasin-B is removed from the medium, heartbeat recovers and myofibrils with discrete Z-bands reappear. Fibrillar sensitivity appears to be a function of age since fibrils in hearts of embryos having from 22 to 28 pairs of somites are more resistant.
No takes yet. Share an insight, caveat, or question.
Manasek et al. (1972) studied Developing cardiac muscle cells. Cytochalasin-B was evaluated on Heartbeat and myofibril structure. Cytochalasin-B reversibly disrupts existing myofibrils, inhibits new myofibril formation, and stops heartbeat in cultured 11- to 13-somite chick embryos.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: