| First Author | Gorlova A | Year | 2020 |
| Journal | J Affect Disord | Volume | 272 |
| Pages | 440-451 | PubMed ID | 32553388 |
| Mgi Jnum | J:302406 | Mgi Id | MGI:6508255 |
| Doi | 10.1016/j.jad.2020.04.014 | Citation | Gorlova A, et al. (2020) Stress-induced aggression in heterozygous TPH2 mutant mice is associated with alterations in serotonin turnover and expression of 5-HT6 and AMPA subunit 2A receptors. J Affect Disord 272:440-451 |
| abstractText | BACKGROUND: The contribution of gene-environment interactions that lead to excessive aggression is poorly understood. Environmental stressors and mutations of the gene encoding tryptophan hydroxylase-2 (TPH2) are known to influence aggression. For example, TPH2 null mutant mice (Tph2-/-) are naturally highly aggressive, while heterozygous mice (Tph2+/-) lack a behavioral phenotype and are considered endophenotypically normal. Here we sought to discover whether an environmental stressor would affect the phenotype of the genetically 'susceptible' heterozygous mice (Tph2+/-). METHODS: Tph2+/- male mice or Tph2+/+ controls were subjected to a five-day long rat exposure stress paradigm. Brain serotonin metabolism and the expression of selected genes encoding serotonin receptors, AMPA receptors, and stress markers were studied. RESULTS: Stressed Tph2+/- mice displayed increased levels of aggression and social dominance, whereas Tph2+/+ animals became less aggressive and less dominant. Brain tissue concentrations of serotonin, its precursor hydroxytryptophan and its metabolite 5-hydroxyindoleacetic acid were significantly altered in all groups in the prefrontal cortex, striatum, amygdala, hippocampus and dorsal raphe after stress. Compared to non-stressed animals, the concentration of 5-hydroxytryptophan was elevated in the amygdala though decreased in the other brain structures. The overexpression of the AMPA receptor subunit, GluA2, and downregulation of 5-HT6 receptor, as well as overexpression of c-fos and glycogen-synthase-kinase-3beta (GSK3-beta), were found in most structures of the stressed Tph2+/- mice. LIMITATIONS: Rescue experiments would help to verify causal relationships of reported changes. CONCLUSIONS: The interaction of a partial TPH2 gene deficit with stress results in pathological aggression and molecular changes, and suggests that the presence of genetic susceptibility can augment aggression in seemingly resistant phenotypes. |
