Abstract
This chapter focuses on the junctional and longitudinal sarcoplasmic reticulum of heart muscle. In heart, muscle contraction is triggered by calcium, which derives from two sources: (1) Extracellular Ca 2+ enters via the plasmalemma during excitation; which then (2) induces Ca 2+ release from sarcoplasmic reticulum (SR). This type of release is referred to as Ca 2+ -induced Ca 2+ release. In fast twitch skeletal muscle, essentially all of the Ca 2+ , which triggers muscle contraction derives from the sarcoplasmic reticulum subsequent to depolarization at the plasmalemma/transverse tubule. This type of release is referred to as "depolarization-induced calcium release. '' In order to study the calcium release mechanism in skeletal muscle, a fraction of junctional terminal cisternae containing well-defined feet structures has been isolated. The feet structures in situ are involved in junctional association with the terminal cisternae to form the triad junction. The calcium release mechanism was found to be modulated by ryanodine at pharmacologically significant concentrations, and has been localized to the terminal cisternae of sarcoplasmic reticulum.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
