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: Although the pharmacology and neurobiology of paranoia remain cryptic , several mechanisms , including 5HT3 receptor - mediated dopamine release , beta - noradrenergic receptor downregulation , or GABAB receptor upregulation acting in the vicinity of the ventral basal ganglia ( possibly in lateral orbitofrontal or anterior cingulate circuits ) , might apply to this phenomenon .
### Output Text:
Although the pharmacology and neurobiology of paranoia remain cryptic , several mechanisms , including 5HT3 receptor - mediated <span class="chemical">dopamine</span> release , beta - noradrenergic receptor downregulation , or GABAB receptor upregulation acting in the vicinity of the ventral basal ganglia ( possibly in lateral orbitofrontal or anterior cingulate circuits ) , might apply to this phenomenon . 