title: The nature of cluster headache.
mesh_terms: D000328:Adult; D001772:Blood Cell Count; D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology; D002560:Cerebrovascular Circulation; D003027:Cluster Headache / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D004569:Electroencephalography; D006632:Histamine / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012701:Serotonin / Q000097:blood; D014653:Vascular Headaches / Q000503:physiopathology*; D014785:Vision, Ocular / Q000502:physiology
chemical_list: D012701:Serotonin; D006632:Histamine