Analysing force-pCa curves
We investigated three forms of the Hill equation used to fit force-calcium data from skinned muscle experiments; Two hyperbolic forms that relate force to calcium concentration directly, and a sigmoid form that relates force to the −log₁₀ of the calcium concentration (pCa). The equations were fit to...
Gespeichert in:
Veröffentlicht in: | Journal of muscle research and cell motility 2010-07, Vol.31 (1), p.59-69 |
---|---|
Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | We investigated three forms of the Hill equation used to fit force-calcium data from skinned muscle experiments; Two hyperbolic forms that relate force to calcium concentration directly, and a sigmoid form that relates force to the −log₁₀ of the calcium concentration (pCa). The equations were fit to force-calcium data from 39 cardiac myocytes (up to five myocytes from each of nine mice) and the Hill coefficient and the calcium required for half maximal activation, expressed as a concentration (EC₅₀) and as a pCa value (pCa₅₀) were obtained. The pCa₅₀ values were normally distributed and the EC₅₀ values were found to approximate a log-normal distribution. Monte Carlo simulations confirmed that these distributions were intrinsic to the Hill equation. Statistical tests such as the t-test are robust to moderate levels of departure from normality as seen here, and either EC₅₀ or pCa₅₀ may be used to test for significant differences so long as it is kept in mind that [graphic removed] is an additive measure of change and that [graphic removed] is a ratiometric measure of change. The Hill coefficient was found to be sufficiently log-normally distributed that log-transformed values should be used to test for statistically significant differences. |
---|---|
ISSN: | 0142-4319 1573-2657 |
DOI: | 10.1007/s10974-010-9208-7 |