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: This depressive - like profile induced by METH was accompanied by a marked depletion of frontostriatal dopaminergic and serotonergic neurotransmission , indicated by a reduction in the levels of dopamine , DOPAC and HVA , tyrosine hydroxylase and serotonin , observed at both 3 and 49 days post - administration .
### Output Text:
This depressive - like profile induced by <span class="chemical">METH</span> was accompanied by a marked depletion of frontostriatal dopaminergic and serotonergic neurotransmission , indicated by a reduction in the levels of <span class="chemical">dopamine</span> , <span class="chemical">DOPAC</span> and <span class="chemical">HVA</span> , <span class="chemical">tyrosine</span> hydroxylase and <span class="chemical">serotonin</span> , observed at both 3 and 49 days post - administration . 