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: The aim of the present study was to find out whether TRI given repeatedly was able to induce adaptive changes in the dopaminergic and alpha1 - adrenergic systems , demonstrated by us previously for various antidepressants .
### Output Text:
The aim of the present study was to find out whether <span class="chemical">TRI</span> given repeatedly was able to induce adaptive changes in the dopaminergic and alpha1 - adrenergic systems , demonstrated by us previously for various <span class="chemical">antidepressants</span> . 