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: Lesions reduced the extent of immunohistological staining for choline acetyltransferase in the interpeduncular nucleus ( p < 0 . 025 ) , but not for tyrosine hydroxylase in the surrounding catecholaminergic A10 region .
### Output Text:
Lesions reduced the extent of immunohistological staining for <span class="chemical">choline</span> acetyltransferase in the interpeduncular nucleus ( p < 0 . 025 ) , but not for <span class="chemical">tyrosine</span> hydroxylase in the surrounding catecholaminergic A10 region . 