title: Cutaneous silent period in hand muscles is lengthened by tramadol: Evidence for monoaminergic modulation?
abstract: The purpose of this study was to shed light on the neurochemical modulatory mechanisms of the noxious spinal inhibitory cutaneous silent period (CSP). We study the effects of 100mg of oral tramadol in 11 healthy volunteers. Tramadol has low affinity for opioid receptors and has the ability to inhibit serotonin and noradrenaline reuptake. We elicited CSPs in the first dorsal interosseus muscle and noxious withdrawal flexor reflexes (NWR) in the right biceps femoris muscle before, 30 min and each hour up to the 6th after tramadol. Subjective pain sensation was checked on an 11-point numerical scale. Tramadol increased duration of CSP, and reduced the NWR area under the curve maximally 2h after tramadol and paralleled the reduction of subjective pain perception. We suggest that the monoaminergic action of tramadol reinforces the activity of spinal inhibitory interneurons on α-motoneurons for the hand muscles.
authors.affiliation: "Sapienza" University of Rome, Department of Medico-surgical Sciences and Biotechnologies, Neurology Section, Rome, Italy. overtango@libero.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Pujia
authors.forename: Gianluca
authors.initials: G
authors.lastname: Coppola
authors.forename: Maria G
authors.initials: MG
authors.lastname: Anastasio
authors.forename: Marianna
authors.initials: M
authors.lastname: Brienza
authors.forename: Elisa
authors.initials: E
authors.lastname: Vestrini
authors.forename: Gabriele O
authors.initials: GO
authors.lastname: Valente
authors.forename: Leoluca
authors.initials: L
authors.lastname: Parisi
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.forename: Francesco
authors.initials: F
authors.lastname: Pierelli
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000494:pharmacology*; D004558:Electric Stimulation; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D017288:Pain Threshold / Q000187:drug effects* / Q000502:physiology; D012018:Reflex / Q000187:drug effects* / Q000502:physiology; D014147:Tramadol / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol