Actions of tramadol, its enantiomers and principal metabolite, O-desmethyltramadol, on serotonin (5-HT) efflux and uptake in the rat dorsal raphe nucleus.

  title={Actions of tramadol, its enantiomers and principal metabolite, O-desmethyltramadol, on serotonin (5-HT) efflux and uptake in the rat dorsal raphe nucleus.},
  author={T. A. Bamigbade and Colin Davidson and Richard M. Langford and Jonathan A. Stamford},
  journal={British journal of anaesthesia},
  volume={79 3},
Tramadol is an atypical centrally acting analgesic agent with relatively weak opioid receptor affinity in comparison with its antinociceptive efficacy. Evidence suggests that block of monoamine uptake may contribute to its analgesic actions. Therefore, we have examined the actions of (+/-)-tramadol, (+)-tramadol, (-)-tramadol and O-desmethyltramadol (M1 metabolite) on electrically evoked 5-HT efflux and uptake in the dorsal raphe nucleus (DRN) brain slice, measured by fast cyclic voltammetry… 

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[Pharmacology of tramadol].

Tramadol is a central acting analgesic which has been shown to be effective and well tolerated, and likely to be of value for treating several pain conditions where treatment with strong opioids is not required.

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The results show that tramadol blocks noradrenaline uptake with selectivity as compared to dopamine uptake, and the interaction with the nor adrenaline transporter is stereoselective.

Contribution of monoaminergic modulation to the analgesic effect of tramadol.

1. In humans, the central analgesic effect of tramadol 100 mg orally is only partially reversed by the opioid antagonist naloxone (0.8 mg intravenously). As suggested by in vitro and animal data

Complementary and synergistic antinociceptive interaction between the enantiomers of tramadol.

A rational explanation for the coexistence of dual components to tramadol-induced antinociception appears to be related to the different, but complementary and interactive, pharmacologies of its enantiomers and might form the basis for understanding its clinical profile.

Opioid and nonopioid components independently contribute to the mechanism of action of tramadol, an 'atypical' opioid analgesic.

The results suggest that tramadol-induced antinociception is mediated by opioid (mu) and nonopioid (inhibition of monoamine uptake) mechanisms, and is consistent with the clinical experience of a wide separation between analgesia and typical opioid side effects.

Drug-Induced Changes in the Release of 3H-Monoamines from Field Stimulated Rat Brain Slices

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