Pharmacological studies on the structure-activity relationship of morphine antagonists.
D000818:Animals; D000996:Antitussive Agents / Q000494:pharmacology*; D007977:Levallorphan / Q000494:pharmacology*; D051381:Rats; D012119:Respiration / Q000187:drug effects*
D000996:Antitussive Agents; D007977:Levallorphan