Figure 1. Examples of expressed Ca_V2.2 (₁B) VDCCs: (a) single-channel current at +15 mV (₁B, ₂-1 ₂a) and (b) ensemble average current obtained by summation of many single-channel current traces. The complementary deoxyribonucleic acid for the calcium channel subunits was transfected into a cell line that contained no endogenous calcium channels so that the properties of the channel could be investigated in isolation. The experiment was performed as described by Meir et al. (2000).

Figure 2. LVA and HVA channel types. DHP, dihydropyridine.

Figure 3. Model of the  Ca²⁺channel oligomeric complex. (a) Topology of the ₁ subunit, showing the S4 transmembrane segments, containing a motif of positively charged amino acid residues, and the P regions between S5 and S6. (b) Putative structure of the oligomeric VDCC complex. The region of association of the subunit is not yet known. AID, interaction domain; BID, interaction domain. Modified from Walker and De Waard (1987). Copyright © 1998, with permission from Elsevier Science.

Figure 4. Idealized neuron with most prevalent distribution of VDCCs. Different neuronal cell types have widely varying complements of VDCCs; for example, they may not express T-type currents. The bold letters indicate the predominant distributions of the different VDCC subtypes, when they are present.