title: Presynaptic inhibition of primary afferents.
mesh_terms: D000344:Afferent Pathways / Q000503:physiopathology*; D006801:Humans; D009474:Neurons / Q000502:physiology; D009619:Nociceptors / Q000502:physiology; D010146:Pain / Q000503:physiopathology*; D011957:Receptors, Opioid / Q000502:physiology; D013569:Synapses / Q000503:physiopathology*
chemical_list: D011957:Receptors, Opioid