Rockefeller University Press

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)	4.3^{^a}	6.2^{^b}	3.1^{^c}	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

	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)	4.3^{^a}	6.2^{^b}	3.1^{^c}	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.

Katz and Miledi, 1967.

Chapman and Tunstall, 1981.

Hodgkin and Horowicz, 1960.