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: Male rats received the noradrenaline neurotoxin DSP4 ( 50 mg / kg ) 7 days prior to injection of D - amphetamine ( 10 or 40 mumol / kg i . p . ) .
### Output Text:
Male rats received the <span class="chemical">noradrenaline</span> neurotoxin <span class="chemical">DSP4</span> ( 50 mg / kg ) 7 days prior to injection of <span class="chemical">D - amphetamine</span> ( 10 or 40 mumol / kg i . p . ) . 