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: Conscious SHR ( male 300 - 350 g ) were subjected to 90 degrees head - up tilts for 60 s following acute administration of prazosin ( 0 . 1 mg kg - 1 i . p . ) or rauwolscine ( 3 mg kg - 1 i . v . ) .
### Output Text:
Conscious SHR ( male 300 - 350 g ) were subjected to 90 degrees head - up tilts for 60 s following acute administration of <span class="chemical">prazosin</span> ( 0 . 1 mg kg - 1 i . p . ) or <span class="chemical">rauwolscine</span> ( 3 mg kg - 1 i . v . ) . 