TABLE I.
Definition of Symbols and Relevant Equations in the Text
| Symbol | Definition | Equation |
|---|---|---|
| ε (a, b) | Extinction coefficient of species at wavelength b | 1 |
| A dye(λ) | Absorbance due to dye (ApIII or phenol red) at wavelength λ | 4, 6 |
| CaSR(t) | Total Ca2+ concentration in SR per unit myoplasmic volume | 7 |
| CaSR(0) | Initial CaSR(t), maximum during a set of pulses | 7 |
| [Ca]SR | Total Ca2+ concentration in SR per unit SR volume | 7 |
| [Ca2+]SR | Free [Ca2+] in SR per unit SR volume | |
| CaSR(∞) | Remnant CaSR when [H+] is steady at end of depleting pulse | A1 |
 ≲t
|
Ca2+ release flux, quantity per unit myoplasmic volume per second | 8, 13 |
c
t
|
Ca2+ release flux, corrected to constant CaSR = CaSR(0) | 8, 13, 16, 17 |
| P(t) | SR permeability × SR surface/volume × [Ca2+]SR/[Ca]SR | 9 |
| τ | Time constant of fit to [H+](t), approx. equal to P −1 | 14 |
| Δ[H+]T | Change in total [H], stoichiometrically related to Δ[Ca2+]T | 11 |
| Δ[Ca2+]T | Total, or cumulated, Ca2+ release | |
| d[H+]/dt | Rate of change of [H+](t), related to  ≲t
|
12 |
| (d[H+]/dt)off | Initial rate of change of [H+](t) after a depleting pulse | A4 |
| α | Myoplasmic H+ buffering power, defined linearly | 10, S6 |
| β | H+ buffering power, defined logarithmically | 11, S3 |
| a, b | Channel activation and inactivation variables | 18 |
| k f, k r, K | Channel inactivation rate constants and equilibrium constant | 19, 20 |
| c 1 | Ratio of [Ca2+] at inactivation sites and fraction of open channels | 21 |
All symbols were introduced in materials and methods. Equations numbered A# are in appendix and S# are in the online supplemental material.