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: Effects of 5 - HT1B receptor ligands microinjected into the accumbal shell or core on the cocaine - induced locomotor hyperactivity in rats .
### Output Text:
Effects of 5 - HT1B receptor ligands microinjected into the accumbal shell or core on the <span class="chemical">cocaine</span> - induced locomotor hyperactivity in rats . 