Figure 3.

Membrane potential and external Ca2+ concentration affect inhibitory actions of FM1-43. (A) Inhibition of MA currents at -70, -35 and +35 mV holding potentials (Caps- neurons, RA currents, n = 7). Activity was indistinguishable at -70 mV (69.7 ± 4.3% inhibition) and -35 mV (70.3 ± 2.1%) but was significantly lower at +35 mV (34.1 ± 2.1%, Student's paired t-test, P < 0.01). Top, example traces from the same cell. (B) Effect of Ca2+ on FM1-43 activity. Increasing external Ca2+ from 2 to 4 mM decreased the inhibitory activity of FM1-43 by 37.4 ± 9.8% (n = 3, Student's paired t-test, P < 0.05) whereas removing external Ca2+ (no chelator included) increased the effect of FM1-43 to 142.2 ± 4.5% of control levels (n = 6, Student's paired t-test, P < 0.05).

Drew and Wood Molecular Pain 2007 3:1   doi:10.1186/1744-8069-3-1
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