In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Cocaine - induced anxiety was also attenuated in Dbh + / - mice following administration of disulfiram , a dopamine beta - hydroxylase ( DBH ) inhibitor .
### Output Text:
<span class="chemical">Cocaine</span> - induced anxiety was also attenuated in Dbh + / - mice following administration of <span class="chemical">disulfiram</span> , a <span class="chemical">dopamine</span> beta - hydroxylase ( DBH ) inhibitor . 