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: Reserpine ( 1 mg / kg ) , administered once every other day for 4 days , produced increases in orofacial dyskinesia , tongue protrusion and vacuous chewing in mice , which are signs indicative of tardive dyskinesia .
### Output Text:
<span class="chemical">Reserpine</span> ( 1 mg / kg ) , administered once every other day for 4 days , produced increases in orofacial dyskinesia , tongue protrusion and vacuous chewing in mice , which are signs indicative of tardive dyskinesia . 