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: Neuroprotective action of MPEP , a selective mGluR5 antagonist , in methamphetamine - induced dopaminergic neurotoxicity is associated with a decrease in dopamine outflow and inhibition of hyperthermia in rats .
### Output Text:
Neuroprotective action of <span class="chemical">MPEP</span> , a selective mGluR5 antagonist , in <span class="chemical">methamphetamine</span> - induced dopaminergic neurotoxicity is associated with a decrease in <span class="chemical">dopamine</span> outflow and inhibition of hyperthermia in rats . 