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: Population responses in granule cells of the dentate gyrus were examined in transverse slices of the ventral hippocampus from pilocarpine - treated and untreated mice .
### Output Text:
Population responses in granule cells of the dentate gyrus were examined in transverse slices of the ventral hippocampus from <span class="chemical">pilocarpine</span> - treated and untreated mice . 