The current information on how stress hormones affect the brain may need reassessment, researchers said in a new study. They found that the effect of mineralocorticoid receptors (MRs) on genomes in the brain’s hippocampus cannot be predicted only by the effect of stress on the glucocorticoid hormone.

Researchers from the University of Bristol studied the binding of MRs and glucocorticoid receptors (GRs) to genes in the hippocampus of the brain’s limbic system, after a stressful event. They found that the binding of MRs to genes was low under non-stressful conditions but increased under stress. This stood in stark contrast with previous research, according to which the binding of MRs to genes was high in both situations.

The binding of GRs to genes, however, complied with existing information. The binding is low in non-stressful conditions and increases when stressors are introduced.

“These novel findings are a significant step forward in our understanding of how glucocorticoid hormones act on the brain after stressful events. They allow for the first time identification of genes within the hippocampus of the brain that are directly affected by GR/MR binding after stress,” Hans Reul, co-author of the study, said in a statement released last Thursday. “Given that stress-related psychiatric diseases such as major depression, anxiety and PTSD are an ever-increasing burden in our society, these new insights are important to find novel treatments and therapies in the future.”

MRs and GRs can also bind together at the same site within the genes in the hippocampus after stress and can possibly boost gene expression, according to the researchers. The study was published in the Proceedings of the National Academy of Sciences journal.

According to the researchers, this is the first study that shows strong evidence in vivo backing the heterodimerising of MR and GR. The study also strongly backs that MRs may need the presence of GRs to bind to specific target genes.