title: Changes in brain tryptophan and tyrosine following acute and chronic morphine administration.
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D013997:Time Factors; D014364:Tryptophan / Q000378:metabolism*; D014443:Tyrosine / Q000097:blood / Q000378:metabolism*
chemical_list: D009270:Naloxone; D014443:Tyrosine; D009020:Morphine; D014364:Tryptophan