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ABSTRACT As a response to environmental cues, maternal glucocorticoids (GCs) may trigger adaptive developmental plasticity in the physiology and behavior of offspring. In North American red squirrels (Tamiasciurus hudsonicus), mothers exhibit increased GCs when conspecific density is elevated, and selection favors more aggressive and perhaps more active mothers under these conditions. We tested the hypothesis that elevated maternal GCs cause shifts in offspring behavior that may prepare them for high-density conditions. We experimentally elevated maternal GCs during gestation or early lactation. We measured two behavioral traits (activity and aggression) in weaned offspring using standardized behavioral assays. Because maternal GCs may influence offspring hypothalamic–pituitary–adrenal (HPA) axis dynamics, which may in turn affect behavior, we also measured the impact of our treatments on offspring HPA axis dynamics (adrenal reactivity and negative feedback), and the association between offspring HPA axis dynamics and behavior. Increased maternal GCs during lactation, but not gestation, slightly elevated activity levels in offspring. Offspring aggression and adrenal reactivity did not differ between treatment groups. Male, but not female, offspring from mothers treated with GCs during pregnancy exhibited stronger negative feedback compared with those from control mothers, but there were no differences in negative feedback between lactation treatment groups. Offspring with higher adrenal reactivity from mothers treated during pregnancy (both controls and GC-treated) exhibited lower aggression and activity. These results suggest that maternal GCs during gestation or early lactation alone may not be a sufficient cue to produce substantial changes in behavioral and physiological stress responses in offspring in natural populations.
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The Use of Guanfacine to Mediate Anxiety-related Reactivity and Reduce Associated Agonistic Behavior in Two Pigtail Macaques ( Macaca nemestrina )
Guanfacine, an α2adrenoceptor agonist, has been used to successfully treat self-injurious behavior in nonhuman primates, including macaques (Macaca mulatta) and baboons (Papio anubis). It does so by facilitating a correction to the dopaminergic system that mediates a reduction in impulsivity and reactivity. Given this, we assessed the potential efficacy of guanfacine to treat socially directed agonistic behavior in primates with an apparent reactive behavioral phenotype. We present data from 2 pigtail macaques (Macaca nemestrina): an intact adult male housed in a breeding group, and an experimentally naive adult female living in a research setting with her social partner. Baseline behavioral assessments suggested that both macaques showed extreme responses to external stressors that triggered them to aggress social partners often leading to wounding that required veterinary intervention. Both animals were tracked during the course of 1 y. Once treated regularly with guanfacine, both animals showed significant reduction in their agonistic behavior and the rate at which they wounded other animals. Indeed, in the year since the female has been treated with guanfacine she has never wounded her cagemate. By collecting regular and detailed behavioral observations on the male in the breeding colony, we were able to identify triggers for his aggression and to track the behavioral changes evidenced after guanfacine treatment. These data supported our hypothesis that his aggression reflected extreme reactivity to external stressors, rather than general anxiety. Importantly, we saw only a limited and short-lived reduction in the male's affiliative behavioral rates, and thus guanfacine had no sedative effect, but did successfully reduce his reactivity and resultant agonism and wounding.
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- Award ID(s):
- 1852338
- PAR ID:
- 10548393
- Publisher / Repository:
- Ingenta Connect
- Date Published:
- Journal Name:
- Comparative Medicine
- Volume:
- 74
- Issue:
- 3
- ISSN:
- 1532-0820
- Page Range / eLocation ID:
- 186 to 194
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.30802/AALAS-CM-24-000001
