title: Diurnal variation in excitation of dorsal horn units by naloxone in the spinal cat suggests a circulating opioid factor.
mesh_terms: D000818:Animals; D002415:Cats; D002940:Circadian Rhythm / Q000187:drug effects*; D004723:Endorphins / Q000502:physiology*; D009270:Naloxone / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D010812:Physical Stimulation; D013116:Spinal Cord / Q000166:cytology* / Q000601:surgery
chemical_list: D004723:Endorphins; C032828:circulating opioid factor; D009270:Naloxone