Physiology Shorts: Regulation of longitudinal muscle motor activity скачать в хорошем качестве

Physiology Shorts: Regulation of longitudinal muscle motor activity

In this Physiology Shorts video, Bernard Drumm (Dundalk Institute of Technology, Ireland) talks about his latest study investigating regulation of longitudinal muscle motor activity in the gastrointestinal tract. Read more in The Journal of Physiology: Pacemaker function and neural responsiveness of subserosal interstitial cells of Cajal in the mouse colon Bernard T. Drumm, Benjamin E. Rembetski, Katelyn Messersmith, Marena S. Manierka, Salah A. Baker & Kenton M. Sanders 598(4), pp. 651-681 https://physoc.onlinelibrary.wiley.co... Transcript: My name is Bernard Drumm, I’m an Assistant Lecturer in the Department of Life & Health Science at Dundalk Institute of Technology, Ireland. This work was conducted at the University of Nevada, Reno and we investigated how rhythmic contractions in longitudinal muscle of the colon are generated. We used a mouse model with a genetically encoded-Ca2+ indicator, GCaMP, that was expressed in smooth muscle cells, to visualize propagating Ca2+ waves in the longitudinal muscle layer of the colon. We found that contractions and propagating Ca2+ waves in this muscle layer were inhibited by antagonists of Ca2+-activated-Cl- channels that were encoded by Ano1. In the gut, Ano1 channels are not expressed in smooth muscle, but instead are expressed in interstitial cells of Cajal or ICC. It’s been known for over 10 years that a class of Ano1 expressing ICC at the level of the subserosa are electrically connected to the longitudinal muscle, but apart from that virtually nothing was known about the function of these cells. The great thing about the recent advances in optogenetics is that you can now ask questions that you simply couldn’t before. So, we investigated the activity of these sub-serosal ICC or ICC-SS, using in situ Ca2+ imaging with an ICC-specific GCaMP. We found that ICC-SS are dynamically active in situ, firing hundreds of Ca2+ events per minute. We used spatio-temporal mapping and particles analysis routines to characterize this activity and the pathways responsible for its generation. We also found that stimulation of nitrergic nerves activated inhibitory neural responses in ICC-SS. So our data suggest that ICC-SS can serve as both pacemaker cells and neuroeffector cells to the longitudinal muscle in the colon. Using the optogenetic techniques and Ca2+ imaging analysis tools from this study, we are now investigating other smooth muscle organs in my new position in Ireland. Thank you very much for taking the time to learn more about our work. Please reach out to me at [email protected] if you would like to talk more.