SEROTONIN METABOLISM IN CHRONIC TENSION-TYPE HEADACHE

Serotonergic neurons play a major role in the regulation of pain and m ay therefore also be involved in the pathophysiology of tension-type h eadache. Platelets are important in the regulation of the free seroton in level in plasma and may be a model of serotonergic neurons. The aim of the present study was to investigate the peripheral serotonin (5HT ) metabolism in patients with chronic tension-type headache. The 5HT l evels in platelets and in plasma, the beta-thromboglobulin (beta-TG) l evels in plasma, and the urinary excretion of 5-hydroxyindoleacetic ac id (5HIAA) were measured in 40 patients with chronic tension-type head ache and in 40 healthy controls. The platelet uptake index was calcula ted as the ratio between platelet 5HT and plasma 5HT levels. There wer e no significant differences in platelet 5HT, plasma 5HT, beta-TG, or 5HIAA between patients and controls. The platelet uptake index was sig nificantly lower in patients 243 (136-367) than in controls 352 (202-5 08), p=0.03. Our results indicate that the peripheral 5HT metabolism i s largely normal in patients with chronic tension-type headache.