A genetic mutation recently discovered by Finnish scientists reduces fear and anxiety, and increases social interaction in mice.
Geneticist Heikki Tanila and colleagues from the University of Eastern Finland used a genetic manipulation technique to remove the P4h-tm gene from the rodent genome and observed an unexpected change in their behavior.
What is a genetic mutation?
It is a modification (accidental or provoked) of the information of the DNA sequence of a gene in the genome of an animal.
Behaviors reviewed and corrected
The mice that had been removed from P4h-tm showed greater courage and did not show learned helplessness, unlike their congeners whose gene had remained functional. Learned helplessness is a permanent and general feeling of helplessness that results from the experience of an animal.
The research team first evaluated the mice using a battery of behavioral tests that included a new type of experiment measuring their panic reaction.
The rodents were placed in an airtight box which was first filled with ambient air and then with 10% carbon dioxide.
A high concentration of carbon dioxide induces an innate reaction that resembles suffocation sensation in animals (humans too) and can lead to panic attacks.
In the experiment, the mice to which the P4h-tm gene had been subtracted froze much less than the control mice in response to the gas exposure.
In social interaction tests, genetically modified mice were significantly more sociable than those in the control group.
In addition, these studies have shown a link between the anatomy of the brain and a behavioral phenotype: the expression of the P4h-tm gene is particularly high in the amygdala, a brain structure that plays a key role in the control of emotional reactions including fear and anxiety.
Did you know?
- About 12% of Canadians have anxiety disorders.
- Women are twice as likely to be infected as men.
- The World Health Organization estimates that 300 million people suffer from anxiety disorders, and as many suffer from depression.
If the effect of the P4h-tm gene on the emotional reactions of mice is now observed, a therapeutic application in humans is not for tomorrow.
This work could still lead to the discovery of neurochemical mechanisms that regulate emotions in humans, and eventually to develop new antidepressants and anxiolytics.
The details of this study are published in the journal Neuropharmacology.