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: Following discontinuation of SNP , blood pressure in the control animals rebounded to 94 torr , as compared with 78 torr in the saralasin - treated rats .
### Output Text:
Following discontinuation of <span class="chemical">SNP</span> , blood pressure in the control animals rebounded to 94 torr , as compared with 78 torr in the <span class="chemical">saralasin</span> - treated rats . 