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: In the present study , the authors induced orofacial dyskinesia by acute reserpine and subchronic haloperidol administration to rats .
### Output Text:
In the present study , the authors induced orofacial dyskinesia by acute <span class="chemical">reserpine</span> and subchronic <span class="chemical">haloperidol</span> administration to rats . 