Erythropoietin increases P_o and open time of Ca²⁺ channels. Patches were formed in day 10 BFU-E–derived erythroblasts bathed in media devoid of Na⁺ and K⁺ (Materials and Methods). Pipette solution contained 30 mmol/L Ba²⁺ as charge carrier and Vp was at −20 mV. (A) Baseline tracings. Ca²⁺ channel openings are indicated by upward transitions. (B) Same patch after bath addition of Epo (2 U/mL). (C) Amplitude histogram and Gaussian fit for channel shown in (B). (D) and (E) Life-time histograms and exponential fit for channels shown in (A) and (B), respectively. Composite data are shown in Table 2.