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 10 mg / kg dose of LY274614 was effective in antagonizing the depletion of dopamine in the striatum , when given as long as 8 hr prior to amphetamine but not when given 24 hr prior to amphetamine .
### Output Text:
A 10 mg / kg dose of <span class="chemical">LY274614</span> was effective in antagonizing the depletion of <span class="chemical">dopamine</span> in the striatum , when given as long as 8 hr prior to <span class="chemical">amphetamine</span> but not when given 24 hr prior to <span class="chemical">amphetamine</span> . 