Table I. Features of excitation–response coupling.
| Coupling
|
||||
|---|---|---|---|---|
| E-S | Cardiac E-C | Skeletal E-C | E-T | |
| Input–output speed | ms | ms | ms | s–min |
| Relationship to voltage (mV/e-fold change) | 4.3a | 6.2b | 3.1c | 5.6 |
| Requires Ca2+ flux through membrane Ca2+ channels | Yes | Yes | No | Yes |
| Voltage dependence above and beyond Ca2+ flux | No | No | Yes | Yes |
| Locally mediated signaling | Yes | Yes | Yes | Yes |
| Requires Ca2+ release from stores | No | Yes | Yes | No |
| Target of Ca2+ or conformational coupling | synaptotagmin | RyRs | RyRs | CaM/CaMKII |
Results in bold are from the present study.