Fig. 5.

Electrophysiology of two A1b isoforms (PA1b-F and AG41) on insect Sf9 cells. Concentration dependent blockage of Sf9 cells ramp membrane current by AG41 and PA1b. a membrane currents recorded in response to voltage ramps of 1.5 s duration applied from −100 to 90 mV in the absence (control) and presence of increasing concentrations of AG41 (upper traces) and PA1b (lower traces). b mean concentration-response data for AG41 (○) and PA1b (●) inhibition of ramp membrane current, measured at +50 mV. Each point represents the mean ± S.E. of n = 8–9 independent experiments. Hill equations were fitted to the data, with 100 % blockage taken as the fixed maximum effect, yielding EC₅₀ values of 14.6 ± 0.4 nM (n = 9, Hill coefficient 1.4 ± 0.1) and 415.3 ± 75.6 nM (n = 8, Hill coefficient 1.7 ± 0.2) for AG41 and PA1b, respectively