According to a team of researchers, a new type of gene mutation that reduces fear and anxiety and also adds to social interaction in a development that could possibly help alleviate depression and social anxiety, conditions that affect over 300 million people globally. This discovery was published in the journal Neuropharmacology. It said that employed gene manipulation technology to remove the ‘P4h-tm’ gene from the mouse genome and found an unexpected change in mouse behaviour. ‘P4h-tm’ knockout mice showed striking courage and a lack of learned helplessness compared to congenic wild-type mice with a functional ‘P4h-tm’ gene.
For the research, the research team assessed mice with a large behavioural test battery that included a novel type of test for the panic reaction. The mice were placed in an air-tight box that was first filled up with regular room air and with 10 percent carbon dioxide.
An elevated concentration of carbon dioxide induces an innate freezing reaction that is thought to resemble the feeling of suffocation in patients suffering from panic attacks.
‘P4h-to’ knockout mice displayed substantially less freezing than control mice in response to carbon dioxide exposure. In tests for social interaction, ‘P4h-tm’ knockout mice made clearly more contact with another mouse than the controls.
Additionally , behavioural tests were routinely used for screening anti-anxiety and anti-depressant drugs revealed reduced fear, anxiety and learned helplessness in ‘P4h-tm’ knockout mice. The study also found a connection between brain anatomy and the behavioural phenotype: the expression of the ‘P4h-tm’ gene was especially high in the amygdala that plays a key role in controlling emotional reactions, including fear and anxiety.
“Our findings are really interesting; we know that the deficiency of the ‘P4H-TM’ gene results in severe developmental defects in humans. However, in light of present knowledge, we cannot tell whether these harmful effects arise from embryonic development or whether they would also appear if the function of the ‘P4H-TM’ protein was inhibited in the adult age,” said Heikki Tanila, one of the researchers.
“In an ideal experiment, ‘P4h-tm’ would be turned off only in the amygdala of an adult mouse,” Dr Leinonen added.
Anxiety disorders and depression are a huge global problem. According to the World Health Organization (WHO), almost 300 million individuals worldwide suffer from anxiety disorders, and over 300 million suffer from depression.