New Type of Antidepressant Found to Work in Mice

Researchers from John Hopkins have found that a compound, called CGP3466B, elicited antidepressant-like effects when administered to mice. These effects occurred within hours, unlike currently available antidepressants, such as fluoxetine, whose effects are not perceptible until weeks or months of use.

CGP3466B has previously been shown to block the receptors in the brain responsible for creating feelings of craving towards cocaine. The researchers decided to see if these compound could be applied as an antidepressant after studying the anaesthetic ketamine, which at low-doses is a fast-acting antidepressant. However, ketamine is highly addictive and therefore cannot be used for prolonged periods of time. CP3466B acts on a similar protein network to ketamine, so they investigated to see if it has similar activity.

To measure the effects of the compound on mice, the researchers used two behavioural tests that are used to discern depressed behaviour in mice. They tested how long it took mice to give up escaping a pool of water and the time it took the mice to enter an unfamiliar, unsheltered environment to retrieve a piece of food. In the first test, the mice given CGP3466B spent on average half a minute more trying to escape. In the second experiment, the treated mice entered the new environment almost twice as fast.

CGP3466B has previously been shown to be nontoxic and nonaddictive in humans, which means the team are optimistic about its clinical uses. However, it has been estimated that it may take several more years before the compound can enter phase II clinical trials, in which its use as an antidepressant for people can be assessed.

The original paper can be found here.

Photo: Steven Snodgrass, Flickr.