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: A question arises whether the reuptake inhibition is of any importance to the adaptive changes induced by repeated antidepressants , suggested to be responsible for the antidepressant activity .
### Output Text:
A question arises whether the reuptake inhibition is of any importance to the adaptive changes induced by repeated <span class="chemical">antidepressants</span> , suggested to be responsible for the <span class="chemical">antidepressant</span> activity . 