/span><span  title="Neuron" class="an Neuron">cells</span><span  title="" class="an ">&ensp;</span>The <span  title="" class="an ">&ensp;</span>effect <span  title="" class="an ">&ensp;</span>of <span  title="" class="an ">&ensp;</span>pre <span  title="" class="an ">&ensp;</span>exposure <span  title="" class="an ">&ensp;</span>of <span  title="" class="an ">&ensp;</span>several <span  title="" class="an ">&ensp;</span>vanilloid <span  title="" class="an ">&ensp;</span>and <span  title="" class="an ">&ensp