title: Actions of morphine and met-enkephalin-amide on nociceptor driven neurones in substantia gelatinosa and deeper dorsal horn.
abstract: Simultaneous recordings of responses of substantia gelatinosa and deep dorsal horn neurones to thermal noxious cutaneous stimulation were made in spinalized cats anaesthetized with urethane/chloralose. Morphine, whether applied iontophoretically in the substantia gelatinosa (50-200 nA) or injected intravenously (1.0-1.5 mg/kg), enhanced the responses of the substantia gelatinosa cells while depressing those of deep cells. Met-enkephalin-amide (50-200 nA) also had similar reciprocal actions. Naloxone counteracted these effects of the agonists. The results support our previous proposal that the opiates facilitate the activity of a substantia gelatinosa system that controls the responses of deep dorsal horn neurones to pain.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008839:Microelectrodes; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D009474:Neurons / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D013376:Substantia Gelatinosa / Q000502:physiology*
chemical_list: D009270:Naloxone; D004744:Enkephalin, Methionine; C021055:Met-enkephalinamide; D009020:Morphine