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: Intravenous pretreatment of the rats with diazepam , although causing no change in the adrenaline - induced pressor effect , did enhance the adrenaline - induced reflex bradycardia .
### Output Text:
Intravenous pretreatment of the rats with <span class="chemical">diazepam</span> , although causing no change in the <span class="chemical">adrenaline</span> - induced pressor effect , did enhance the <span class="chemical">adrenaline</span> - induced reflex bradycardia . 