rMargatoxin

Electrophysiological recordings from either Xenopus oocytes expressing cloned channels or from human peripheral T lymphocytes (expressing predominantly K_v1.3), were examined to confirm the ability of Margatoxin to inhibit potently (< 1 nM) K_v1.3 K⁺ channels.^{1, 2}

Inhibition of heterologously expressed K_v1.3 channels by 10 nM of rMargatoxin (above).

Left: time course of current amplitude change, upon application of toxin. Currents were recorded with extracellular ND96 solution and were elicited every 10 seconds by 100 ms pulse to 0 mV (holding potential was ?00 mV). The bar represents period of toxin perfusion.

Right: superimposed example traces before (red) and during (black) application of 10 nM rMargatoxin.

Potent inhibition of K_V currents in Jurkat cells by low dose rMargatoxin (above).

Left: Time course of Jurkat cells K_V current (at 0 mV) inhibition by 8.6 nM rMargatoxin. Currents were elicited from holding potential of ?0 mV, by 500 ms voltage ramps from ?20mV to +50mV, every 10 seconds. Current traces were not corrected for leak and amplitude was measured at 0 mV. Period of toxin perfusion is indicated by the horizontal bar.

Right: Example of current voltage relationship (generated by plotting the current response against the stimulating voltage ramp, with no leak subtraction), before and during application of rMargatoxin.

Margatoxin inhibits VEGF induced cell migration of Human Umbilical Vein Endothelial Cells (HUVECs) (above).

HUVECs were tested in an 8 mm-pore transwell inserts in a Chemokinetic Migration Assay with or without 20ng/ml VEGF in the lower chamber as chemoattractant, in presence or absence of 5 mM rMargatoxin in both chambers. The results presented are an average of cells number in six microscopic fields of each treatment.

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