Table 1.

Solutions for skinned fibre experiments

Solution	Hepes (mM)	Mgtotal§ (mM)	EGTA (mM)	Catotal‖ (mM)	HDTA (mM)	NaN3 (mM)	Caffeine (mM)	ATP (mM)	CP (mM)	pCa
MAS	90	10.3 (1)	50	50	—	1	—	8	10	4.2
HRS	90	10.3 (1)	50	—	—	1	—	8	10	12.8
LRS	90	8.6 (1)	0.2†	—	50	1	—	8	10	9.4
LS	90	8.6 (1)	1.0*	—	50	1	—	8	10	7.7
RS	90	2.0 (0.05)	0.5†	—	50	1	30	8	10	9.9
RSSM	90	5.3 (0.25)	0.5‡	—	50	1	15	8	10	9.9

MAS, maximum activating solution; HRS, high relaxing solution; LRS, low relaxing solution; LS, load solution; RS, release solution; RS_SM, submaximal release solution. All solutions were adjusted to pH 7.4 using 4 M KOH.

^*LS was made by adding 100 μl of HRS and 20 μl of 49 mM CaCl₂ to 5 ml of LRS (lacking EGTA).

^†LRS and RS were initially made without EGTA. EGTA was included by adding 20 or 50 μl of HRS, respectively, to 5 ml of LRS or RS immediately before use.

^‡RS_SM was made by combining 2.5 ml of LRS (without EGTA) with 2.5 ml of RS (lacking EGTA) and then adding 50 μl of HRS.

^§Mg²⁺ was added as MgO; the calculated free [Mg²⁺] is given in parentheses.

^‖Ca²⁺ was added as Ca(CO₃)². HDTA, hexamethylenediamine-tetraacetate; CP, creatine phosphate.