Related Experiment Video
Updated: May 15, 2026

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Endogenous morphine and its metabolites in mammals: history, synthesis, localization and perspectives
A Laux-Biehlmann1, J Mouheiche, J Vérièpe
1Nociception and Pain Department, Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR3212 and Université de Strasbourg, F-67084 Strasbourg, France.
Abstract:
Morphine derived from Papaver somniferum is commonly used as an analgesic compound for pain relief. It is now accepted that endogenous morphine, structurally identical to vegetal morphine-alkaloid, is synthesized by mammalian cells from dopamine. Morphine binds mu opioid receptor and induces antinociceptive effects. However, the exact role of these compounds is a matter of debate although different links with infection, sepsis, inflammation, as well as major neurological pathologies (Parkinson's disease, schizophrenia) have been proposed. The present review describes endogenous morphine and morphine derivative discovery, synthesis, localization and potential implications in physiological and pathological processes.
More Related Videos
Related Concept Videos
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Opioid Analgesics: Morphine and Other Natural Cogeners
Opioid Receptors: Overview
Analgesia and Pain Management
Drug Abuse and Addiction: Pharmacological Phenomena
Phase II Reactions: Methylation Reactions
The mechanism of methylation unfolds in two stages. The first stage sees a methyltransferase enzyme facilitating the transfer of a methyl group from S-adenosylmethionine (SAM) to the substrate, forming S-adenosylhomocysteine (SAH). The second stage involves further metabolism of SAH into homocysteine, which can be recycled...

