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: Our findings demonstrated that ouabain at 10 ( - 2 ) and 10 ( - 3 ) M induced hyperlocomotion in rats , and this response remained up to 7 days following a single ICV injection .
### Output Text:
Our findings demonstrated that <span class="chemical">ouabain</span> at 10 ( - 2 ) and 10 ( - 3 ) M induced hyperlocomotion in rats , and this response remained up to 7 days following a single ICV injection . 