Content of Monoamines in the Pons Varolii in Experimental Post-Traumatic Stress Disorder

Abstract—In posttraumatic stress disorder (PTSD), the development of anxiety symptoms correlates with an increase in the content of noradrenaline and dopamine and a decrease in the content of serotonin in the limbic structures of the brain. Unfortunately, the character of changes in the level of monoamines in the brain stem structures such as the pons Varolii is not known, although it is damaged in patients with PTSD. The aim of the study was to determine the content of monoamine-neurotransmitters and their metabolites in the pons Varolii under the conditions of experimental PTSD. To reproduce the symptoms of PTSD, a predator stress model was used by exposing rats to the smell of a cat. The level of anxiety was determined using an elevated plus maze. High performance liquid chromatography was used to determine the concentrations of noradrenaline, dopamine, and the metabolite of dopamine, dihydroxyphenylacetic acid. It was found that under experimental PTSD, the content of noradrenaline in the pons Varolii decreased. At the same time, the content of dopamine and serotonin did not undergo significant changes. The content of noradrenaline negatively correlated with the anxiety index. In the pons Varolii, there were no changes in the level of monoamines typical of PTSD. In contrast to limbic structures, we observed a decrease in the level of noradrenaline with a constant level of other monoamines and their metabolites.