We have located links that may give you full text access.
A study of the mechanisms of excitation-contraction coupling in frog skeletal muscle based on measurements of [Ca 2+ ] transients inside the sarcoplasmic reticulum.
Journal of Muscle Research and Cell Motility 2018 April
[Ca2+ ] transients inside the sarcoplasmic reticulum (SR) were recorded in frog skeletal muscle twitch fibers under voltage clamp using the low affinity indicator Mag Fluo 4 (loaded in its AM form) with the purpose of studying the effect on Ca2+ release of extrinsic Ca2+ buffers (i.e. BAPTA) added at high concentration to the myoplasm. When the extrinsic Ca2+ buffer is added to the myoplasm, part of the released Ca2+ binds to it, reducing the Ca2+ signal reported by a myoplasmic indicator. This, in turn, hinders the quantification of the amount of Ca2+ released. Monitoring release by measuring [Ca2+ ] inside the SR avoids this problem. The application of extrinsic buffers at high concentration reduced the resting [Ca2+ ] in the SR ([Ca2+ ]SR ) continuously from a starting value close to 400 μM reaching the range of 100 μM in about half an hour. The effect of reducing resting [Ca2+ ]SR on the Ca2+ permeability of the SR activated by voltage clamp depolarization to 0 mV was studied in cells where the myoplasmic [Ca2+ ] ([Ca2+ ]myo ) transients were simultaneously recorded with Rhod2. The Ca2+ release flux was calculated from [Ca2+ ]myo and divided by [Ca2+ ]SR to obtain the permeability. Peak permeability was significantly reduced, from 0.026 ± 0.005 ms-1 at resting [Ca2+ ]SR = 372 ± 5 μM to 0.021 ± 0.004 ms-1 at resting [Ca2+ ]SR = 120 ± 16 μM (n = 4, p = 0.03). The time averaged permeability was not significantly changed (0.009 ± 0.003 and 0.010 ± 0.003 ms-1 , at the higher and lower [Ca2+ ]SR respectively). Once the cells were equilibrated with the high buffer intracellular solution, the change in [Ca2+ ]SR (Δ[Ca2+ ]SR ) in response to voltage clamp depolarization (0 mV, 200 ms) in 20 mM BAPTA was significantly lower (Δ[Ca2+ ]SR = 30.2 ± 3.5 μM from resting [Ca2+ ]SR = 88.8 ± 13.6 μM, n = 5) than in 40 mM EGTA (Δ[Ca2+ ]SR = 72.2 ± 10.4 μM from resting [Ca2+ ]SR = 98.2 ± 15.6 μM, n = 4) suggesting that a Ca2+ activated component of release was suppressed by BAPTA.
Full text links
Related Resources
Trending Papers
Challenges in Septic Shock: From New Hemodynamics to Blood Purification Therapies.Journal of Personalized Medicine 2024 Februrary 4
Molecular Targets of Novel Therapeutics for Diabetic Kidney Disease: A New Era of Nephroprotection.International Journal of Molecular Sciences 2024 April 4
Perioperative echocardiographic strain analysis: what anesthesiologists should know.Canadian Journal of Anaesthesia 2024 April 11
The 'Ten Commandments' for the 2023 European Society of Cardiology guidelines for the management of endocarditis.European Heart Journal 2024 April 18
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app