Scientists at the Max Planck Institute for Experimental Medicine in Göttingen, Germany, have identified a protein which, when inactivated, has an anxiolytic effect in mice.
Anxiety disorders are linked to an increased neuronal activity in the amygdala. Many anxiolytic medications such as benzodiazepines help normalize this over activation by strengthening the function of inhibitory synapses. But this can lead to significant side effects, which the study published in the Nature Communication journal on December 20, tried to overcome.
Generally, synapses are connections between nerve cells in the brain, at which information is transmitted from one nerve cell to another. At inhibitory synapses, this transmission results in a reduction in the activity of the amygdala, to inhibit the transmission of stimuli that trigger fear and anxiety.
Benzodiazepines strengthen this inhibitory effect, but, unfortunately they affect not only those inhibitory synapses, but also many other inhibitory synapses in the brain.
This can lead to significant side effects such as pronounced sedation and impaired concentration, which prompted scientists to search for new, more specific targets for anxiolytic medications.
The study aimed at blocking the production of the recently discovered protein IgSF9b in mice. The protein has been proved to produce a protein bridge at inhibitory synapses between two neighboring nerve cells that enhance anxiety feelings. However, blocking IgSF9b prevents the transmissions of these feelings among cells.
Olga Babaev from the Max Planck Institute for Experimental Medicine who carried out the experiments as part of her doctoral work, said: "In the study we had two groups of mice that were released in an empty room. The first showed anxiety symptoms and isolated itself in one of the room's corners, while the other moved in the room freely and without fear.”
“When we inhibited the production of IgSF9b protein, the worried animals moved freely around the room again. This result makes us seek a future in which we target this protein with anxiety medications, to avoid the side effects of current drugs," she added.
