File:A-Novel-Striated-Muscle-Specific-Myosin-Blocking-Drug-for-the-Study-of-Neuromuscular-Physiology-Video4.ogv

English: Development of fatigue in response to HFS in embryonic WT diaphragm expressing GCaMP3. E15.5 CAGGS-GCaMP3 mice were stimulated in the absence of BHC to illustrate the concordance of fiber shortening and calcium transient intensity. Note the progressive loss in maintenance of peak calcium transient intensity in response to increasing nerve stimulation frequency. Note also that despite the ability of diaphragm to maintain peak or near-peak shortening in response to 10 Hz for the entire 30-s period, an undulating pattern of intermittent fluorescence occurs toward the end of stimulation, which appears to presage fatigue, because this pattern of fluorescence occurs earlier and more profoundly in response to 20 Hz stimulation. Finally, note the “spontaneous” activation of bands of muscle fibers in all conditions before nerve stimulation, likely representing the spontaneous release of transmitter that occurs in response for several hours after nerve severance.