Figure 3.

Ba²⁺ antagonizes Ca²⁺ currents in the presence of higher concentration of K⁺ channel blockers. (a) shows control response. (b) shows response 6 min after the beginning of superfusion with 2 mM Ba²⁺. This solution contained normal calcium with 10 mM TEA, 200 μM DAP, and procaine (100 μM, to prevent repetitive firing) and generated a longer duration Ca²⁺ current. This effect of Ba²⁺ was reversible (data not shown, but see Figure 6). Each trace is the average of two responses (frequency of stimulation=0.01 Hz).