Membrane tension modulates TRESK-like currents in trigeminal sensory neurons.

<p><b>A.</b> Total whole-cell K⁺ current of a small trigeminal sensory neuron in the presence of 2 µM TTX. Currents were elicited by a depolarizing ramp from −90 to +50 mV. Holding voltage was −60 mV. A 10% hypertonic solution produces a significant decrease of the current. <b>B.</b> Membrane current from a trigeminal neuron recorded at +20 mV in the presence of TTX (2 µM), 4-Aminopyridine (4-AP, 1 mM), Tetraethylammonium (TEA, 1 mM) and Iberiotoxin (IbTx, 50 nM). In these conditions and at room temperature, most of the current measured should be carried by TRESK. 10% hypertonic solution produces a significant decrease of the current. <b>C.</b> Similar experiment as in B but with total K⁺ current activated with a depolarizing ramp from −90 to +50 mV. <b>D.</b> Example of a recording in a trigeminal neuron using a protocol to minimize activation of voltage-gated transient K⁺ outward currents and in the presence of Na⁺ and K⁺ blockers. Hypertonic medium produced a significant reduction of the activated current. <b>E.</b> Quantification of the experiments performed in A (n = 11) and C (n = 8). <b>F.</b> Quantification of currents recorded as in D. Measurements were done at the end of the pulse (−25 mV) and at the end of the ramp (−135 mV; n = 8). *p<0.05; **p<0.01; ***p<0.001 Wilcoxon non-parametric test vs. baseline current.