An international team of researchers have discovered a possible link between autism-like behavior in mice and exposure to a common anti-depressant during pregnancy. According to a report this month by Science Daily.com, the researchers also identified a treatment that helped improve social interaction and memory loss. The study was published in the scientific journal Molecular Brain.
The researchers, led by Duke-NUS medical school, focused on the antidepressant Fluoxetine, a commonly prescribed medication. However, little is known about the drug’s safety during pregnancy, or its potential long-term effects on offspring. The research team, along with collaborators in South Korea and Singapore, studied adult mice born to mothers treated with Fluoxetine over a 15-day period that corresponds to the second trimester in humans. Those mice were contrasted with others who had been given normal saline during pregnancy.
The researchers identified key differences in behavior between the adult mice whose mothers had been treated with Fluoxetine, and the unexposed mice. For example, the mice that had not been exposed to Fluoxetine explored all three arms of a Y-shaped maze over a 10-minute time period. Over the course of multiple entries, most mice usually enter a less visited arm. This was something that the mice who had been exposed to Fluoxetine were less inclined to do.
The researchers also conducted a second experiment, in which the mice were introduced to two younger mice, one after the other. When the second mouse was introduced, the mice that had not been exposed to Fluoxetine were more likely to only sniff that mouse, realizing that they had already met the first one. However, the Fluoxetine exposed group sniffed both mice, suggesting impaired social novelty recognition.
Following this experiment, the researchers examined nerve signal transmission in the pre-frontal cortex of the Fluoxetine exposed mice (the pre-frontal cortex is a region of the brain connected with controlling social behavior). The researchers found impaired transmission caused by an overactive serotonin receptor. The behavioral problems and memory of the Fluoxetine exposed mice improved after they were treated with a compound that blocks the overactive receptor.
For their next step, the researchers plan to study autistic children born to mothers treated with anti-depressants. As part of their study, the researchers will use positron emission topography (PET) scans, an imaging technique used to observe metabolic processes in the body. If the scans show enhanced serotonin activity in the same region of the brain, the team will test whether FDA-approved serotonin receptor blockers can normalize the children’s behavior.