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: Therefore , like VPA , the finding that VPU could drastically reduce pilocarpine - induced increases in glutamate and aspartate should account , at least partly , for its anticonvulsant activity observed in pilocarpine - induced seizure in experimental animals .
### Output Text:
Therefore , like <span class="chemical">VPA</span> , the finding that <span class="chemical">VPU</span> could drastically reduce <span class="chemical">pilocarpine</span> - induced increases in <span class="chemical">glutamate</span> and <span class="chemical">aspartate</span> should account , at least partly , for its anticonvulsant activity observed in <span class="chemical">pilocarpine</span> - induced seizure in experimental animals . 