tle="" class="an ">&ensp;</span>basal <span  title="" class="an ">&ensp;</span>modulation <span  title="" class="an ">&ensp;</span>by <span  title="" class="an ">&ensp;</span>cyclic <span  title="" class="an ">&ensp;</span>nucleotide <span  title="" class="an ">&ensp;</span>Members <span  title="" class="an ">&ensp;</span>of <span  title="" class="an ">&ensp;</span>the <span  title="" class="an ">&ensp;</span><span  title="CAP" class="an CAP">HCN</span><span  title="" class="an ">&ensp;</span>channel <span 