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: MK - 801 , a noncompetitive N - methyl - D - aspartate ( NMDA ) receptor antagonist , was tested for anticonvulsant effects in rats using two seizure models , coadministration of lithium and pilocarpine and administration of a high dose of pilocarpine alone .
### Output Text:
<span class="chemical">MK - 801</span> , a noncompetitive <span class="chemical">N - methyl - D - aspartate</span> ( <span class="chemical">NMDA</span> ) receptor antagonist , was tested for anticonvulsant effects in rats using two seizure models , coadministration of <span class="chemical">lithium</span> and <span class="chemical">pilocarpine</span> and administration of a high dose of <span class="chemical">pilocarpine</span> alone . 