Comparative Effects of Heterologous TRPV1 and TRPM8 Expression in Rat Hippocampal Neurons
Figure 3
Menthol induces large depolarizing currents in TRPM8-transfected neurons.
(A) Fluorescence image of a neuron in mass culture transfected with synaptophysin-YFP (Syn-YFP) and TRPM8. Scale bar denotes 50 µm. (B) Phase contrast image of the same field as (A). (C) Example of a Syn-YFP/TRPM8-transfected neuron recorded in cell-attached patch configuration in voltage-clamp mode during 5 s 100 µM menthol application (top trace) or 5 s 30 mM KCl application (bottom trace). Note that action potentials were elicited by both treatments in the same cell. (D) Example of a non-transfected neuron recorded under the same conditions as (C). Note that action potentials were only elicited during KCl application. (E) Example of a Syn-YFP/TRPM8-transfected neuron recorded in whole-cell voltage-clamp during 10 s acute 100 µM menthol or 30 mM KCl application. TRPM8-transfected neurons responded with robust currents to both menthol and KCl application. (F) Example of a non-transfected neuron recorded under the same conditions as (E). Non-transfected neurons did not respond to menthol but always responded with robust currents to KCl at the holding potential of −70 mV. (G) A non-transfected neuron recorded in whole-cell voltage clamp held at 0 mV during 15 s acute application of 100 µM menthol with 100 µM picrotoxin added during the last 5 s. Note that picrotoxin decreased the current gated by menthol.
