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 results support the hypothesis that the protective activity of loreclezole and its combinations with other antiepileptics may involve potentiation of GABAergic neurotransmission and blockade of L - type of calcium channels .
### Output Text:
The results support the hypothesis that the protective activity of <span class="chemical">loreclezole</span> and its combinations with other antiepileptics may involve potentiation of GABAergic neurotransmission and blockade of L - type of <span class="chemical">calcium</span> channels . 