The synchronous indirect flight muscle (DLM1) is located in the thorax of the Hawk moth, Manduca sexta. It has the potential to be a model... Show moreThe synchronous indirect flight muscle (DLM1) is located in the thorax of the Hawk moth, Manduca sexta. It has the potential to be a model system for cardiac muscle because both muscles have similar length-tension curves and they have similar passive properties (Tu & Daniel, 2004). An important and valuable property of the muscle is the temperature gradient between dorsal and ventral muscles which have a corresponding functional gradient between them. The functions of dorsal and ventral muscle appear to be regulated by the temperature gradient and changes in the phase of activation (N. T. George, Sponberg, & Daniel, 2012). Very little is known, however, about its other physiological properties. Here I measured the relation between tetanic tension and sarcomere length in chemical skinned dorsal and ventral muscle in order to further characterize the properties of the two muscle parts. Analysis of the results showed similarities and differences in the length of thick and thin filaments, maximum force, and rates of force generation between dorsal and ventral muscles. Maximal force was also plotted as a function of temperature in order to inquire into the physiological changes of muscle at various temperatures. The potential of DLM1 to be a model system for some aspects of cardiac muscle research was supported by the results of this study. The hypothesis that functions of dorsal and ventral muscle is regulated by the temperature gradient and changes in the phase of activation also was verified. M.S. in Biology, May 2015 Show less
