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: There was no change in the levels of DA , norepinephrine ( NE ) , serotonin ( 5 - HT ) , or their metabolites in the arcuate nucleus ( AN ) , medial preoptic area ( MPA ) , caudate putamen ( CP ) , substantia nigra ( SN ) , and zona incerta ( ZI ) , except for a decrease in 5 - hydroxyindoleacetic acid ( 5 - HIAA ) in the AN after 6 - months of hyperprolactinemia and an increase in DA concentrations in the AN after 9 - months of hyperprolactinemia .
### Output Text:
There was no change in the levels of <span class="chemical">DA</span> , <span class="chemical">norepinephrine</span> ( <span class="chemical">NE</span> ) , <span class="chemical">serotonin</span> ( <span class="chemical">5 - HT</span> ) , or their metabolites in the arcuate nucleus ( AN ) , medial preoptic area ( MPA ) , caudate putamen ( CP ) , substantia nigra ( SN ) , and zona incerta ( ZI ) , except for a decrease in <span class="chemical">5 - hydroxyindoleacetic acid</span> ( <span class="chemical">5 - HIAA</span> ) in the AN after 6 - months of hyperprolactinemia and an increase in <span class="chemical">DA</span> concentrations in the AN after 9 - months of hyperprolactinemia . 