Figure 1. Patch excision alters voltage... | Rockefeller University Press

Figure 1.

$Figure 1. Patch excision alters voltage gating of Elk1. (A) Schematic drawing of on-cell and excised inside-out recording configurations. Currents recorded in response to a 2-s voltage ramp (−120 to 80 mV; −100-mV holding potential) are shown for the on-cell (black) and excised (red) configurations, with high K+ in the pipette. Arrows point to the increased inward current at hyperpolarized voltages and the rapid deactivation that gradually occur upon patch excision. (B) Peak tail current amplitude at −100 mV (from ramp recordings as in A) increases upon excision and stabilizes within 5–10 min. Data (n = 8) were normalized to the first sweep after excision. (C) Elk1 currents recorded in response to a series of 1-s voltage steps (−120 to 60 mV in 20-mV increments; −100-mV holding potential) on cell and after excision and stabilization. Note the fast activation and deactivation in the excised recording (arrows). (D) On-cell and excised G-V curves for Elk1. Data were measured from isochronal tail currents recorded at −100 mV after 1-s steps to the indicated voltages (n = 32 and 37, respectively). Curves show single Boltzmann fits of the data (V50 and s reported in Table 1). (E) Elk1 activation time constants measured at 60 mV before and after excision. Activation rate speeds up and stabilizes by 6–8 min after excision (n = 13); the inset compares normalized current traces recorded at −20 mV (polarity flipped for display purposes). (F) Comparison of on-cell (n = 15) and excised (n = 26) activation time constants at various voltages. (G) Deactivation kinetics for Elk1 on cell and excised as measured by the fractional tail current amplitude 60 ms after repolarization to −100 mV (lower value = faster deactivation; n = 8). (Inset) Normalized tail currents at −100 mV after 2-s prepulse to 60 mV (dotted line, zero current). Data in all panels show mean ± SEM.$

Patch excision alters voltage gating of Elk1. (A) Schematic drawing of on-cell and excised inside-out recording configurations. Currents recorded in response to a 2-s voltage ramp (−120 to 80 mV; −100-mV holding potential) are shown for the on-cell (black) and excised (red) configurations, with high K⁺ in the pipette. Arrows point to the increased inward current at hyperpolarized voltages and the rapid deactivation that gradually occur upon patch excision. (B) Peak tail current amplitude at −100 mV (from ramp recordings as in A) increases upon excision and stabilizes within 5–10 min. Data (n = 8) were normalized to the first sweep after excision. (C) Elk1 currents recorded in response to a series of 1-s voltage steps (−120 to 60 mV in 20-mV increments; −100-mV holding potential) on cell and after excision and stabilization. Note the fast activation and deactivation in the excised recording (arrows). (D) On-cell and excised G-V curves for Elk1. Data were measured from isochronal tail currents recorded at −100 mV after 1-s steps to the indicated voltages (n = 32 and 37, respectively). Curves show single Boltzmann fits of the data (V₅₀ and s reported in Table 1). (E) Elk1 activation time constants measured at 60 mV before and after excision. Activation rate speeds up and stabilizes by 6–8 min after excision (n = 13); the inset compares normalized current traces recorded at −20 mV (polarity flipped for display purposes). (F) Comparison of on-cell (n = 15) and excised (n = 26) activation time constants at various voltages. (G) Deactivation kinetics for Elk1 on cell and excised as measured by the fractional tail current amplitude 60 ms after repolarization to −100 mV (lower value = faster deactivation; n = 8). (Inset) Normalized tail currents at −100 mV after 2-s prepulse to 60 mV (dotted line, zero current). Data in all panels show mean ± SEM.