pan>a <span  title="" class="an ">&ensp;</span>hyperpolarization <span  title="" class="an ">&ensp;</span>activated <span  title="" class="an ">&ensp;</span>cyclic <span  title="" class="an ">&ensp;</span>nucleotid <span  title="" class="an ">&ensp;</span>gated <span  title="" class="an ">&ensp;</span>cation <span  title="" class="an ">&ensp;</span>channel <span  title="" class="an ">&ensp;</span><span  title="CAP" class="an CAP">HCN</span><span  title="" class="an ">&ensp;</span>mediated <span  title="" cl