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: Oral administration of KF17837 ( 2 . 5 , 10 . 0 and 30 . 0 mg / kg ) significantly ameliorated the cataleptic responses induced by intracerebroventricular administration of an adenosine A2A receptor agonist , CGS 21680 ( 10 micrograms ) , in a dose - dependent manner .
### Output Text:
Oral administration of <span class="chemical">KF17837</span> ( 2 . 5 , 10 . 0 and 30 . 0 mg / kg ) significantly ameliorated the cataleptic responses induced by intracerebroventricular administration of an <span class="chemical">adenosine</span> A2A receptor agonist , <span class="chemical">CGS 21680</span> ( 10 micrograms ) , in a dose - dependent manner . 