Figure 3.

The β₁ subunit still increases both burst duration and the duration of gaps between bursts in 0 Ca²⁺ _i when P _o is increased by depolarization. (A and B) Currents recorded from single α and α+β₁ channels at two different membrane potentials of +60 mV (A) and +90 mV (B) in 0 Ca²⁺ _i. For the +60-mV data, a continuous record was cut into two traces in each case. The average P _os for the entire records from which the excerpts were obtained were: 0.0042 (+60 mV) and 0.063 (+90 mV) for the α channel, and 0.029 (+60 mV) and 0.37 (+90 mV) for the α+β₁ channel. (C) Representative bursts of openings from A and B on a faster time base. α channel, C96; α+β₁ channel, C100.