>&ensp;</span>a <span  title="" class="an ">&ensp;</span>recently <span  title="" class="an ">&ensp;</span>discovered <span  title="" class="an ">&ensp;</span>neuropeptide <span  title="" class="an ">&ensp;</span>that <span  title="" class="an ">&ensp;</span>structurally <span  title="" class="an ">&ensp;</span>resembles <span  title="" class="an ">&ensp;</span>an <span  title="" class="an ">&ensp;</span>opioid <span  title="" class="an ">&ensp;</span>peptide <span  title="" class="an ">&ensp;</span>The <sp