Table 2.

Effect of Gβ₁γ₂ on channel activity

Amplitude, pA	Activity before Gβγ, openings per s	Activity after Gβγ, openings per s
1.5–1.7	5.8  ± 0.88	5.6  ± 2.1
3.3–3.5	0.19  ± 0.05	3.8  ± 1.3

n = 8. Data were recorded with the inside-out mode at −91 mV. Short-duration openings were eliminated (see Fig. 4 legend). Almost all channels within 1.5–1.7 pA would represent KirNB, whereas almost all channels within 3.3–3.5 pA would belong to GIRKs (see Results). Frequency of the channel activity within 1.5–1.7 pA (KirNB) was not increased by the Gβ_1γ2 (paired t test, P = 0.9). In contrast, the frequency of the channels in the 3.3- to 3.5-pA range (GIRK) was increased markedly (paired t test; P < 0.001).