title: Characteristics of extravascular serotonin receptors in the brain.
abstract: At least three types of extravascular 5-HT receptors are present in the brain. Peripheral 5-HT antagonists mimic the inhibitory effects but block the excitatory effects 5-HT in the brain. Although the forebrain serotonergic system is apparently not involved in nociception, the MPR may be an important link in an antinociceptive system; this system may be activated by morphine. A decrease in the amount of 5-HT released by projections from the MPR to the trigeminal nucleus could be partially responsible for the pain experienced in migraine headache. Drugs useful in treating migraine headache may mimic 5-HT at synapses in the trigeminal nucleus that are associated with projections from the MPR. This possibility remains to be tested experimentally.
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D002415:Cats; D006801:Humans; D008881:Migraine Disorders / Q000209:etiology / Q000503:physiopathology; D009020:Morphine / Q000494:pharmacology; D009474:Neurons / Q000502:physiology; D010146:Pain / Q000503:physiopathology; D011903:Raphe Nuclei / Q000502:physiology; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012684:Sensory Thresholds; D014278:Trigeminal Nuclei / Q000502:physiology
chemical_list: D011985:Receptors, Serotonin; D009020:Morphine