Doxycycline will protect against post-stress syndrome
The formation of traumatic memories was weakened by an antibiotic
Oleg Lischuk, N+1
Swiss and British scientists have discovered that the well-known antibiotic doxycycline is able to prevent excessive fixation on traumatic memories underlying post-traumatic stress disorder. The results of the work are published in the journal Molecular Psychiatry (Bach et al., Blocking human fear memory with the matrix metalloproteinase inhibitor doxycycline).
Learning to anticipate threats is a fundamental property of many living organisms that helps to avoid dangers. In cases where such foresight becomes excessive (as a rule, it occurs as a result of traumatic events, such as military operations, terrorist attacks, disasters, and others), post–traumatic stress disorder (PTSD) develops - a condition in which the slightest associations with a traumatic event cause a powerful negative mental reaction (anxiety, panic, depression, nightmares, etc.).
In recent decades, a set of data has been obtained indicating that proteins of the extracellular matrix of the brain, in particular the enzyme matrix metalloproteinase type 9 (MMP9, gelatinase B), participate in the remodeling of synapses necessary for the fixation of memories.
Researchers at the University of Zurich and University College London conducted a small double-blind clinical trial to find out whether the tetracycline antibiotic doxycycline, which is also a brain-penetrating inhibitor of MMR9, can affect the formation of traumatic memories. To participate in the experiment, they invited 76 healthy adult volunteers.
During the first phase of the trials, participants were randomly divided into two equal groups, one of which received 200 milligrams of doxycycline (a standard single dose), and the other received a placebo. After that, the volunteers were shown randomly alternating red and blue colors on the monitor, while one of the colors in half of the cases was accompanied by a tangible electric shock. To consolidate the memory, the colors were changed 160 times.
After that, the participants were invited to return in a week. The demonstration of colors was repeated, but instead of an electric shock, the "bad" color was accompanied by a loud beep. Before the session, the volunteers were tested for the strength of negative memories, comparing their reaction to the signal given with "good" and "bad" colors. During the viewing, the degree of fright of the participants was recorded by the natural reaction of blinking and changes in the electrical conductivity of the skin.
It turned out that with the preliminary appointment of doxycycline, the formed memories of the threat are about 60 percent weaker than after taking a placebo. At the same time, the drug did not have a significant effect on sensory memories.
"The use of medications to prevent PTSD is difficult, because in the real world we do not know when a traumatic event will occur. Nevertheless, there is evidence that memories and associations can be changed when a person gets into a situation similar to receiving a mental trauma or imagines it – this phenomenon is called reconsolidation. Now we plan to study the effect of doxycycline on the reconsolidation of traumatic memories, and if we succeed, we hope to start testing such therapy on more realistic clinical models of PTSD within a few years," said lead author Dominik Bach in a press release UCL Common antibiotic may help to prevent or treat PTSD.
Earlier, scientists found out that playing tetris can weaken the formation of traumatic memories. A potential drug to help with severe PTSD is methylenedioxymethamphetamine ("ecstasy") – in The US has for the first time allowed its large-scale clinical trials to be used for this indication.
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05.04.2017