title: The dual-system hypothesis of pain perception.
abstract: We describe a dual-system hypothesis relating the seemingly contradictory findings reported in clinical and experimental investigations of pain. This incorporates a model in which two neuronal systems are related, involving Substance P (SP) and Enkephalin (E). This model uses feedback loops holding the systems in balance. The analogy to a control system is also made.
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D004723:Endorphins / Q000502:physiology*; D004745:Enkephalins / Q000502:physiology*; D005246:Feedback; D006801:Humans; D009433:Neural Inhibition; D009474:Neurons / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology; D011963:Receptors, GABA-A; D011957:Receptors, Opioid / Q000502:physiology; D012684:Sensory Thresholds; D013116:Spinal Cord / Q000502:physiology*; D013373:Substance P / Q000502:physiology*; D009435:Synaptic Transmission
chemical_list: D004723:Endorphins; D004745:Enkephalins; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D011957:Receptors, Opioid; D013373:Substance P