Central monoaminergic systems sensitivity to acute hypoxia with hypercapnia changes after the maintenance under the long-term social isolation

Abstract

The experiments were performed in male albino outbred mice kept in a group and under the conditions of long-term social isolation. The changes in the monoaminergic systems of the left and right hemispheres of the brain after acute hypoxia with hypercapnia have been studied. The levels of dopamine (DA), serotonin (5-HT) and their metabolites – dioxyphenylacetic (DOPAC), homovanillic (HVA), and 5-hydroxyindoleacetic (5-HIAA) acids – were determined by HPLC in the cerebral cortex, hippocampus and striatum of the right and left sides of the brain. In the control mice kept both in the group and under the conditions of social isolation, a higher content of DA in the cortex of the left hemisphere has been found. In the other brain structures the monoamine content was symmetric. In the cerebral cortex of the mice in the group, acute hypoxia with hypercapnia led to a right-sided increase in the DA and 5HT levels. At the same time, the DOPAC content decreased in the left cortex. In mice in the group, under the hypoxia with hypercapnia conditions, the DA level in the left hippocampus increased. In the striatum, the content of monoamines and their metabolites did not change significantly. In animals kept for a long time under the conditions of social isolation, hypoxia with hypercapnia no statistically significant changes in the monoamines and their metabolites levels were found. It has been concluded that the preliminary maintenance under the conditions of prolonged social isolation changes the reaction of central monoaminergic systems to acute hypoxia with hypercapnia.