In thirty patients with common migraine the platelet concentrations of met-enkephalin immunoreactivity (ME) (76 +/- 9 pg/mg protein) were similar to those in 23 healthy volunteers (77 +/- 5), suggesting that there is no alteration in the ME pool in this biochemical compartment in migraine. Chronic treatment (4 weeks) with drugs that interfere with 5-hydroxytryptamine (5-HT) synthesis or uptake induced the expected changes in platelet 5-HT levels, i.e. a rise following administration of the 5-HT precursor 5-hydroxytryptophan (daily dose: 300-500 mg, n = 9) and a decrease after amine uptake inhibition by amitryptyline (30-75 mg, n = 7) and even more by chlorimipramine (30-50 mg, n = 9). Platelet ME concentrations rose by up to approximately 90% over the basal values after either 5-hydroxytryptophan (significantly from week 2) or amitriptyline (at week 2) and were unchanged after chlorimipramine, indicating that 5-HT and ME concentrations in platelets can vary independently. The high platelet ME levels following 5-hydroxytryptophan and amitriptyline cannot be explained at present. They might be due either to increased ME synthesis, possibly in the megakaryocyte, or to decreased utilization by platelets or both.
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Article Synopsis
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- The research indicates that the extensive distribution of M
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