Predator stress induces behavioral inhibition and amygdala somatostatin receptor 2 gene expression

Abstract

Psychological stressors precipitate and maintain stress-induced psychopathology, and it is likely that altered amygdala function underlies some of the deleterious effects of psychological stress. To understand the mechanisms underlying the linkage between the response to psychological stressors and maladaptive or psychopathological responses, we have focused on amygdala responsivity in animal models employing species-specific psychological stressors. In the present study, we characterized the effects of a 15-min exposure to a natural predator, the ferret, on rat behavior and the expression of the somatostatin family of genes in the amygdala. We examined the somatostatin family of genes because substantial evidence shows that central somatostatin systems are altered in various neuropsychiatric illnesses. We report that rats respond to acute ferret exposure with a significant increase in fearful and anxious behaviors that is accompanied by robust amygdala activation and an increase in somatostatin receptor 2 (sst2) messenger RNA expression within the amygdala and anterior cingulate cortex. These studies are the first to show stress-induced changes in amygdala sst2 expression and may represent one mechanism by which psychological stress is linked to adaptive and maladaptive behavioral responses.

Brain Transcriptomic Response of Threespine Sticklebacks to Cues of a Predator

“…We found that 10% of the transcripts were differentially expressed (p ^ 0.01) between fish exposed to cues of a predator and a control group. These patterns are consistent with other studies involving predator cues [Nanda et al, 2008;Leder et al, 2009]. For example, a 15-min exposure to ferret olfactory, visual and acoustic cues increased stress-like behavior in rats and resulted in the differential expression of 7% of genes in the amygdala 3 h after exposure to a predator [Nanda et al, 2008].…”

“…This procedure elicited enduring changes in stickleback growth and behavior [Dingemanse et al, 2009;Bell et al, 2011], and other studies using this population have shown that they exhibit strong antipredator responses to rainbow trout [Bell and Sih, 2007]. Nanda et al [2008] used a similar procedure to measure the immediate brain transcriptomic response of rats to olfactory, visual and acoustic cues of predators. Sticklebacks were exposed to two types of olfactory cues.…”

“…Most studies have measured gene expression within minutes after a single exposure to predation risk [Wang et al, 2003;Nanda et al, 2008;Leder et al, 2009;Mori et al, 2009]. However, animals are often recurrently exposed to cues of predators, and other studies suggest that the response of the hypothalamicpituitary-adrenal axis to acute versus chronic stress is different [McEwen, 2007].…”

“…Important recent studies have shown that exposure to a predator results in the activation of particular neural circuitry in the brain [e.g. Nanda et al, 2008] and that specific genes, including immediate early genes [e.g. Comoli et al, 2003;Blanchard et al, 2005;Motta et al, 2009], are upregulated in the brain in response to the threat of predation.…”

Early life stress stimulates hippocampal reelin gene expression in a sex‐specific manner: Evidence for corticosterone‐mediated action

“…Details of this relative quantification can be found at http://docs.appliedbiosystems.com/pebiodocs/04303859.pdf. All quantifications were normalized to an established internal control for rodent brain (ribosomal S12 protein RNA, housekeeping gene), which was coamplified as described previously by others (Heinrich et al, 2006;Usarek et al, 2006;Nanda et al, 2008). For each group the results were given as mean 6 SEM.…”