Table 2.

Parameters relating to Ca²⁺ sensitivity of cremaster and cerebral VSMCs

[Ca2+]i (μm)	Cremaster mean V1/2 (mV)	Cerebral mean V1/2 (mV)	ΔV1/2 (mV)†
0.5	101.0 ± 9.8	72.0 ± 6.1*	29.0
1.0	56.8 ± 8.9	33.5 ± 5.6*	23.3
3.0	45.6 ± 5.9	20.3 ± 3.6*	25.3
10	11.1 ± 3.6	−17.1 ± 2.6*	28.9
30	−27.6 ± 4.2	−49.2 ± 7.2*	21.6
100	−63.0 ± 6.6	−89.5 ± 8.9*	26.5
			25.8 ± 1.3

^*V_1/2 for cremaster muscle VSMCs is significantly different from that of cerebral VSMCs (P < 0.05).

^†Difference in holding potential (mV) between cremaster muscle and cerebral VSMCs at a given [Ca²⁺] required to give equivalent probability of channel opening.