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: Intrarenal compared with intravenous infusion of noradrenaline caused higher plasma noradrenaline concentrations and a shift of the plasma noradrenaline concentration - blood pressure effect curve towards lower plasma noradrenaline levels .
### Output Text:
Intrarenal compared with intravenous infusion of <span class="chemical">noradrenaline</span> caused higher plasma <span class="chemical">noradrenaline</span> concentrations and a shift of the plasma <span class="chemical">noradrenaline</span> concentration - blood pressure effect curve towards lower plasma <span class="chemical">noradrenaline</span> levels . 