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: Prostanoids may , via release of tachykinins , contribute to both urge and bladder hyperactivity seen in inflammatory conditions of the lower urinary tract .
### Output Text:
<span class="chemical">Prostanoids</span> may , via release of <span class="chemical">tachykinins</span> , contribute to both urge and bladder hyperactivity seen in inflammatory conditions of the lower urinary tract . 