Oxaliplatin Lab Report

To further investigate on the effects of oxaliplatin on the TRPA1 channel activity, we performed electrophysiological patch clamp experiments in the cell attached mode, the recording configuration that less interferes with the intracellular milieu composition. In all experiments DRG neurons were perfused with a bath solution containing 150 mM KCl and low [Ca2+] (see methods), to set the membrane potential near 0. Figure XA shows two records of 30 s long showing the channel activity in an oxaliplatin treated neuron in the presence of 1 M of icilin and of 1.5 mM of [Ca2+] in the pipette solution at Vm= 40 mV (upper trace) and -40 mV (lower trace). Single channel currents were outwards at positive voltages and inwards at negative voltages as expected for a non-selective

Single channel conductance () and reversal potential (Vr) were respectively of 100 pS and of 0 mV for outward currents and of 30 pS and of 0 mV for outward currents. Furthermore, the channel activity (NPo) was voltage-dependent, with high open probability at negative potentials and a a voltage-dependent inactivation at positive potentials (Figure XC). These channel properties are in good agreement with previously published data (Nilius…). A second set of experiment was devoted to chacterize the channel biophysical properties in the absence of divalent ions in the pipette, with the purpose to attenuate calcium-dependent inactivation (Citazione), a prerequisite for long duration experiments. Figure XD shows a record of 30 s long of the patch currents from an oxaliplatin treated neuron in the presence of 1 M of icilin at Vm= 40 mV (upper trace) in which at least three channels were active. Moreover, the red open circles of figure XE represent the single channel current amplitudes recorded at different membrane potentials. In this condition, the fitted regression line yields a and a Vr respectively of 1 00 pS and of 0