Effects of L-5HTP with and without carbidopa on plasma β-endorphin and pain perception: possible implications in migraine prophylaxis |
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Authors: | AR Genazzani G Sandrini F Facchinetti V Rizzo E Alfonsi G Sances M Calvani G Nappi |
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Affiliation: | Department of Obstetrics and Gynecology, University of Modena, Modena, Italy;;Headache Centre, Department of Neurology, University of Pavia, Pavia, Italy;;Department of Clinical Research, Sigma Tau, Pomezia, Rome, Italy |
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Abstract: | L-Tryptophan (L-TP) has been used in migraine and other pain conditions. The mechanism underlying the analgesic effect is still partly undefined. In this study the effects of subchronic administration of L-5-hydroxytryptophan (L-5HTP) (with and without carbidopa) on plasma beta-endorphin (beta-EP) levels and subjective pain threshold and tolerance were investigated in seven healthy volunteers. To measure also an objective indicator of pain, the nociceptive flexion reflex threshold was studied. L-5HTP treatment with and without carbidopa administration increased beta-EP levels significantly (p less than 0.05). L-5HTP plus carbidopa induced an increase in beta-EP significantly (p less than 0.05) greater than that induced by L-5HTP alone. Neither the subjective pain threshold and tolerance nor the RIII threshold was modified by either treatment. Our data seem to point to the existence of a complex linkage between plasma opioid levels and pain perception. |
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Keywords: | b-Endorphin L-5-hydroxytryptophan migraine prophylaxis pain perception |
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