HIV-1 Tat protein enhances outward K⁺ currents (<i>I</i>_out) in rat microglia.

<p><b>A</b>: Representative whole-cell membrane currents recorded from microglia treated with or without Tat at varied concentrations (0, 20, 200, 1000 ng/ml). <b>B</b>: Whole-cell membrane current recordings of microglia treated with heat-inactivated Tat (200 ng/ml). <b>C</b>: Dose-response curve of the Tat-induced effect on <i>I</i>_out. Current densities in response to different concentrations of Tat is calculated (mean ± S.E.M) from 32, 25, 27 and 24 different cells in control, 20 ng/ml, 200 ng/ml, 1000 ng/ml groups. <b>D</b>: Pharmacology of Tat-induced <i>I</i>_out. Tat induced <i>I</i>_out were evoked by voltage from the holding potential −70 mV to +50 mV for 600 ms are shown before and during superfusion with extracellular solution containing 10 nM PAP, 5 nM MgTX, 1 mM 4-AP. <b>E</b>: Blockade of Tat(200 ng/ml) enhancement of <i>I</i>_out by specific Kv1.3 blockers PAP (n = 8) and MgTx (n = 8) or by a broad spectrum K⁺ channel blocker 4-AP (n = 7). # p<0.05 vs Tat; ### p<0.001 vs Tat.