The Sensitivity of Developing Cardiac Myofibrils to Cytochalasin-B
Abstract
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.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- February 1972
- DOI:
- 10.1073/pnas.69.2.308
- Bibcode:
- 1972PNAS...69..308M