Figure 4.

CDI of native IHC Ca²⁺ channels (A) and unchanged CDI of Ca_V1.3 Ca²⁺ channels containing a long α_1D splice variant (B). A, Top, Direct comparison of CDI for native IHC Ca²⁺ channels with that for recombinant Ca_V1.3 channels (r_Ca, recombinant Ca²⁺ current trace, reproduced from Fig. 1B), as labeled. Native currents were evoked by a −15 mV step, and the recombinant current was evoked by a −10 mV step (asterisk). Native current f₃₀₀ = 0.008 ± 0.013 (n = 6). Bottom, Schematic of isolated organ of Corti preparation (P8–P9 rats) from which native recordings were made in the apical turn. Top schematic provides orientation; expanded view below illustrates details of the pipette approach to an IHC. B, CDI exhibited by long splice variant Ca_V1.3 Ca²⁺ channels (α_1Dlg/β_2a/α₂δ). Format as in Figure 1B. Behavior is no different from that for the short splice variant Ca_V1.3 Ca²⁺ channels (α_1Dsh/β_2a/α₂δ), as seen by comparison with dashed curves reproducing fits to control r₅₀ and r₃₀₀ relations in Figure 1B. f₅₀ = 0.62 ± 0.02 (n = 13); f₃₀₀ = 0.60 ± 0.03 (n = 13).