Talk:Morphinan

You have missed out the ether bridge between carbon atoms 4 and 5 - this is neccesary for opioid like actions. I refuse to beleive that methylamphetamine acts in the same way or has similar structures to opioids. Opioids act at defined receptors - mu delta and kappa, producing a cascade of chemical actions in the cell - methamphetamine acts to block the dopamine re-uptake protein at the synapse - thus concentrating dopamine (and to some extent nor-adrenaline) in the synapse - in addition, it encourages the sysnthesis of more dopamine in the pre-synaptic nerve end, but dexamphetamine is better at this than methaphetamine

No, the 4,5-epoxy bridge is not necessary for opioid activity -- see levorphanol, for example.--84.163.107.162 01:59, 14 September 2007 (UTC)

That is not correct: the 4,5-epoxy bridge is required for calling the structure morphinans. Morphinans are the simplified structure based on the morphine backbone. The structure shown here is that of a pro-morphinan which lack the 4,5-epoxy bridge. The first pro-morphinan is synthesised in nature by a P450 enzyme called Salutaridine Synthase, and the last pro-morphinan, the tetra-acyclic salutaridinol-7-acetate, is converted to the first pentacyclic morphinan/opiate alkaloid by thebaine synthase 144.32.241.129 (talk) 16:42, 17 October 2025 (UTC)

Um, I think Codeinone and Morphinone should be removed from the list of morphinans since they have an intact E ring and thus aren't morphinans. Aj1976 08:21, 6 November 2007 (UTC)

Why is the 4,5 bridge an epoxy and not just an ether? —Preceding unsigned comment added by 12.147.63.195 (talk) 14:54, 7 February 2011 (UTC)

The first phrase should be "opiate" instead of "opioid". Please change. — Preceding unsigned comment added by 89.204.139.99 (talk) 21:27, 2 March 2014 (UTC)