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: We therefore conducted the present acute dose - response study in four 1 - methyl - 4 - phenyl - 1 , 2 , 3 , 6 - tetrahydropyridine ( MPTP ) - exposed cynomolgus monkeys primed to exhibit levodopa - induced dyskinesias to evaluate the locomotor and dyskinetic effects on challenge with four doses ( from 0 . 03 to 1 . 0 mg / kg ) of A - 86929 ( [ - ] - [ 5aR , 11bS ] - 4 , 5 , 5a , 6 , 7 , 11b - hexahydro - 2 - propyl - 3 - thia - 5 - + + + azacyclopent - 1 - ena [ c ] phenathrene - 9 - 10 - diol ) , a selective and full DA D1 - like receptor agonist with an intermediate duration of action .
### Output Text:
We therefore conducted the present acute dose - response study in four <span class="chemical">1 - methyl - 4 - phenyl - 1 , 2 , 3 , 6 - tetrahydropyridine</span> ( <span class="chemical">MPTP</span> ) - exposed cynomolgus monkeys primed to exhibit <span class="chemical">levodopa</span> - induced dyskinesias to evaluate the locomotor and dyskinetic effects on challenge with four doses ( from 0 . 03 to 1 . 0 mg / kg ) of <span class="chemical">A - 86929</span> ( <span class="chemical">[ - ] - [ 5aR , 11bS ] - 4 , 5 , 5a , 6 , 7 , 11b - hexahydro - 2 - propyl - 3 - thia - 5 - + + + azacyclopent - 1 - ena [ c ] phenathrene - 9 - 10 - diol</span> ) , a selective and full <span class="chemical">DA</span> D1 - like receptor agonist with an intermediate duration of action . 