Cross‐fostering differentially affects ADHD‐related behaviors in spontaneously hypertensive rats

Abstract

Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered to an unfamiliar dam of either the same or different strain. Behavioral testing took place when the rats reached adulthood. Locomotor hyperactivity was completely dependent on the strain of the offspring. In contrast, social behavior was primarily determined by the strain of the mother, while attentional orienting behavior was influenced by both the strain of the offspring and the strain of the dam. Anxiety-related behavior was influenced by an interaction between offspring and dam strain.

The impact of maternal neglect on genetic hyperactivity

“…Some SHR studies have been conducted on the subject of environment and hyperactivity, but are limited to assessing environmental enrichment interventions during post-weaning periods [38, 39], not negative experiences in early life. Two previous cross-fostering studies of SHRs provide tentative hypotheses for the outcome of the present study [40, 41]. In both cases, cross-fostering SHR pups to either WKY or Sprague-Dawley control dams did not influence activity levels, consistent with our findings.…”

“…Yet these studies preclude foresight of our outcome, due to the fact that 1) WKY maternal care is not an improvement over SHR maternal care [27], and 2) these studies employ a different definition of hyperactivity. Our selective breeding protocol defines hyperactivity as an average activity level over several days in a home cage setting, well after an extended habituated period [14, 15]; SHR hyperactivity in these studies was defined as activity across one fifteen-minute open field test [41] or activity during a ten-minute social-interaction test [40]. Therefore the present study not only corroborates previous findings in a related model of genetic hyperactivity, but also expands on them by first quantifying the vast differences in maternal behavior of both High-Active and Control dams, and then measuring the habituated hyperactivity of large samples of both male and female cross-fostered pups.…”

Enriched Environments as a Potential Treatment for Developmental Disorders: A Critical Assessment

“…Adult SHRs that were raised by typically active WKY mothers did not differ in locomotor hyperactivity from control SHRs raised by SHR mothers ( Howells et al, 2009 ; Gauthier et al, 2015 ). In contrast, hyper-social behavior was dependent on mother’s strain, with both SHR and WKY strains raised by SHR mothers showing increased hyper-sociability ( Gauthier et al, 2015 ). Results indicate that some ADHD-like behaviors seen in the SHR strain are genetically determined ( Howells et al, 2009 ), whereas others might be partially dependent on nurturing by SHR dams.…”

Establishment of the circadian metabolic phenotype strategy in spontaneously hypertensive rats: a dynamic metabolomics study

“…SHRs are a well-known model of essential hypertension [15]. An important feature of the SHR model is that it was originally derived from the normal WKY strain [16]. Therefore, in basic scientific research on the level of hypertension animals, WKYs are used as a normal control group for SHRs [2,[17][18][19].…”