Dextrallorphan

Dextrallorphan (DXA) is an opioid derivative chemical of the morphinan class that is used in scientific research. It acts as a σ₁ receptor agonist and NMDA receptor antagonist. It has no significant affinity for the σ₂, μ-opioid, or δ-opioid receptor, or for the serotonin or norepinephrine transporter. As an NMDA receptor antagonist, in vivo, it is approximately twice as potent as dextromethorphan, and five-fold less potent than dextrorphan.

Uses in Scientific Research

Masking of sigma-1 receptor

Dextrallorphan is often used in research to block σ₁ receptor sites so that σ₂ receptor sites (which have not been cloned yet) can be studied. It was hypothesized that both of these sigma (σ) receptors were opioid receptors, due to their affinity for psychoactive drugs. However, it is now understood that they are non-opioid receptors that bind to certain psychoactive drugs, like dextrallorphan. One example of dextrallorphan being used to mask σ₁ receptor sites was seen in a study on the localization of the σ₂ receptor in detergent-resistant lipid raft domains. It has also been used to mask σ₁ receptor sites so that σ₂ receptor binding characteristics in the rat liver could be determined, by labeling σ₂ receptor sites with [³H]l,3-di-o-tolylguanidine (DTG) in the presence of 1 μM dextrallorphan solution.