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: The present study was designed to study the effect of histamine H ( 3 ) - receptor ligands on neuroleptic - induced catalepsy , apomorphine - induced climbing behavior and amphetamine - induced locomotor activities in mice .
### Output Text:
The present study was designed to study the effect of <span class="chemical">histamine</span> H ( 3 ) - receptor ligands on neuroleptic - induced catalepsy , <span class="chemical">apomorphine</span> - induced climbing behavior and <span class="chemical">amphetamine</span> - induced locomotor activities in mice . 