Brian Trainor Associate Professor Department of Psychology University of California One Shileds Ave. Young Hall Davis, CA. Office phone: 530-752-1672 Email: Brian
Brian Trainor, Behavioral Neuroendocrinology Lab
University of California, Davis, CA.
Research
Current Research Interests
Sex Differences in Effects of Social Stress
One important feature of many mood disorders is that women are almost twice as likely as men to be affected. For a variety of reasons however, most animal models examining neurobiological mechanisms related to depression focus on males. Indeed, there is an urgent need for the development of model systems in which behaviors related to depression and anxiety can be studied in both sexes. The social stress (subordination) paradigm induces pronounced behavioral changes including anhedonia and a marked increase in social avoidance (or withdrawal). However, the overwhelming majority of studies using social stress have focused on males. This is because in most species of rodents, female aggression is minimal, so it is difficult to create social stress using intra-female aggression. In contrast, female California mice (Peromyscus californicus) are aggressive, as males and females defend joint territories. In addition, females have larger corticosterone responses than males during resident-intruder aggression tests. We are using the unique biology of the California mouse to examine sex differences in neurobiological mechanisms that mediate the effects of social stress on affective behaviors.
Estrogens and Aggression
In Peromyscus, it appears that photoperiod determines whether estrogens act via genomic or nongenomic pathways in the brain. In the bed nucleus of the stria terminalis, a brain nucleus that influences aggressive behavior, genes that are estrogen-dependent are upregulated in long days compared to short days. The increased estrogen-dependent gene expression in long days suggests that estrogens may decrease aggression by changing gene expression. In contrast, we demonstrated that an injection of estradiol increases aggressive behavior within 15 minutes when mice are housed in short days. The same estradiol injection has no effect on behavior when mice are housed in long days. Most researchers agree that 15 minutes is not enough time frame for changes in gene expression (and protein) to occur, so this suggests that the effects of estradiol on aggression in short days is occurring though nongenomic pathways. We will be testing this hypothesis by using an estrogen agonist that can not enter the nucleus (thereby preventing changes in gene expression).
Media coverage of research
Science Signal Transduction Knowledge Environment Editor's Choice
Training
Post-doc: Ohio
State University, Randy
Nelson
Post-doc: Harvard University,
Hans Hofmann
PhD: University of Wisconsin, Cathy
Marler
MS: University of Nebraska, Alex
Basolo
BS: University of Texas:
Mike Ryan
Photos by Nicholas DiRienzo and Sarah Laredo