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: These results suggest that down - regulation of hippocampal NET induced by chronic administration of desipramine may be relevant to desipramine - induced sensitization of lidocaine convulsions .
### Output Text:
These results suggest that down - regulation of hippocampal NET induced by chronic administration of <span class="chemical">desipramine</span> may be relevant to <span class="chemical">desipramine</span> - induced sensitization of <span class="chemical">lidocaine</span> convulsions . 