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. 2014 May 1;117(1):53–59. doi: 10.1152/japplphysiol.00253.2014

Fig. 4.

Fig. 4.

Electrophysiological properties of the VDCC in PA and MCA myocytes. A: representative tracings of single channel recordings from PAs and MCAs at different voltages. B: graph showing current-voltage (I-V) relationships of single voltage-dependent calcium channels in myocytes from PAs and MCAs. There was no difference in the single channel conductances between myocytes from PAs (slope conductance: 17.5 ± 0.7 pS) and MCAs (slope conductance: 16.9 ± 0.7 pS). C: graph showing the relationships between membrane potential and steady-state open-state probably (Po) in myoctyes from PAs and MCAs. Data were fitted using the equation Po = Pmax/[1 + exp (V0.5 − Vm)/k], where Pmax is the maximal Po at positive potentials, V0.5 is the membrane potential where Po is one-half Pmax, and k is the steepness factor, which describes the voltage-sensitivity of the calcium channels. There were no differences in these parameters between the two vessel types (PA Pmax: 0.58 ± 0.13, MCA Pmax: 0.52 ± 0.05; PA V0.5: 16 ± 4 mV, MCA V0.5: 11 ± 2 mV; PA k: 6.8 ± 1.4, MCA k: 12.9 ± 1.1).