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: After 180 min of temporary middle cerebral artery occlusion in spontaneously hypertensive rats , the effect of phenylephrine - induced hypertension on ischemic brain injury and blood - brain barrier permeability was determined .
### Output Text:
After 180 min of temporary middle cerebral artery occlusion in spontaneously hypertensive rats , the effect of <span class="chemical">phenylephrine</span> - induced hypertension on ischemic brain injury and blood - brain barrier permeability was determined . 