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: These findings demonstrate for the first time that a single high dose of METH induces long - lasting depressive - like behaviour in mice associated with a persistent disruption of frontostriatal dopaminergic and serotonergic homoeostasis .
### Output Text:
These findings demonstrate for the first time that a single high dose of <span class="chemical">METH</span> induces long - lasting depressive - like behaviour in mice associated with a persistent disruption of frontostriatal dopaminergic and serotonergic homoeostasis . 