The study results have been released by the company Relmada Therapeutics. The results relate to an in vivo study (that is tested within a living creature rather than being run in a test tube) and they demonstrate that the administration of d-Methadone, results in antidepressant-like effects. The effects were apparent after a single administration of the drug. The lowering of depression was confirmed after the animals engaged in a standard model for depression called the forced swim test.
d-Methadone is a N-methyl-d-aspartate (NMDA) receptor antagonist. An antagonist, in medical terms, is a substance which interferes with or inhibits the physiological action of another. d-methadone is a related to methadone (a type of opioid used to treat pain and as maintenance therapy.) However, d-Methadone is designed for the treatment of neuropathic pain (problems with signals from the nerves) and it has virtually no opioid activity.
With the new study, male Sprague Dawley rats were administered single doses of either ketamine (a medication mainly used for starting and maintaining anesthesia and one which induces a trance-like state), or d-Methadone. The results indicated that d-Methadone decreased immobility of the rats compared to the control substance ketamine.
Anti-depressant activity was then assessed by subjecting the rats to the forced swim test. This test looks a rodent’s response to the threat of drowning. Here, where the rodent does not attempt to save itself this is interpreted as a strong susceptibility to a negative mood.
In a statement, Dr. Richard Mangano, from Relmada Therapeutics, said: “This study is the first to clearly demonstrate that d-Methadone exhibits antidepressant-like effects in a well-validated treatment model to predict antidepressant activity.”