title: Microinjection of morphine into the periaqueductal gray evokes the release of serotonin from spinal cord.
mesh_terms: D000818:Animals; D002535:Cerebral Aqueduct / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects; D051381:Rats; D012701:Serotonin / Q000378:metabolism*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*
chemical_list: D012701:Serotonin; D009270:Naloxone; D009020:Morphine