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 findings suggest that helodermin - produced hypotension is partly attributable to the activation of glibenclamide - sensitive K + channels ( K ( ATP ) channels ) , which presumably exist on arterial smooth muscle cells .
### Output Text:
These findings suggest that <span class="chemical">helodermin</span> - produced hypotension is partly attributable to the activation of <span class="chemical">glibenclamide</span> - sensitive <span class="chemical">K</span> + channels ( <span class="chemical">K</span> ( <span class="chemical">ATP</span> ) channels ) , which presumably exist on arterial smooth muscle cells . 