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: CONCLUSION : Activation of pallidal neurotensin receptors may be involved in neurotensin - induced antiparkinsonian effects .
### Output Text:
CONCLUSION : Activation of pallidal <span class="chemical">neurotensin</span> receptors may be involved in <span class="chemical">neurotensin</span> - induced antiparkinsonian effects . 