lass="an ">&ensp;</span>to <span  title="" class="an ">&ensp;</span>activate <span  title="" class="an ">&ensp;</span><span  title="CAP" class="an CAP">HCN</span><span  title="" class="an ">&ensp;</span>In <span  title="" class="an ">&ensp;</span><span  title="Neuron" class="an Neuron">cell</span><span  title="" class="an ">&ensp;</span>free <span  title="" class="an ">&ensp;</span>patches <span  title="" class="an ">&ensp;</span>the <span  title="" class="an ">&ensp;</span>steady <span  title="" class="an 