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Abstract ObjectivesLittle is known about how ilium cortical bone responds to loading. Using a mouse model, this study presents data testing the hypothesis that iliac cross‐sectional properties are altered in response to increased activity. Materials and MethodsThe sample derives from lines of High Runner (HR) mice bred for increased wheel‐running activity. Four treatment groups of female mice were tested: non‐selected control lines housed without (N = 19) and with wheels (N = 20), and HR mice housed without (N = 17) and with wheels (N = 18) for 13 weeks beginning at weaning. Each pelvis was μCT‐scanned, cross‐sectional properties (cortical area—Ct.Ar, total area—Tt.Ar, polar moment of area, and polar section modulus) were determined from the ilium midshaft, and robusticity indices (ratio of the square root ofCt.ArorTt.Arto caudal ilium length) were calculated. Mixed models were implemented with linetype, wheel access, and presence of the mini‐muscle phenotype as fixed effects, replicate line nested within linetype as a random effect, and body mass as a covariate. ResultsResults demonstrate that the mouse ilium morphologically resembles a long bone in cross section. Body mass and the mini‐muscle phenotype were significant predictors of iliac cross‐sectional properties. Wheel access only had a statistically significant effect onCt.Arand its robusticity index, with greater values in mice with wheel access. DiscussionThese results suggest that voluntary exercise increases cortical area, but does not otherwise strengthen the ilium in these mice, corroborating previous studies on the effect of increased wheel‐running activity on femoral and humeral cross‐sectional properties in these mice.
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This content will become publicly available on November 4, 2025
Hippocampal long-term potentiation is modulated by exercise-induced alterations in dopaminergic synaptic transmission in mice selectively bred for high voluntary wheel running
BackgroundHigh-Runner (HR) mice, selectively bred for increased voluntary wheel running behavior, exhibit heightened motivation to run. Exercise has been shown to influence hippocampal long-term potentiation (LTP) and memory, and is neuroprotective in several neurodegenerative diseases. ObjectiveThis study aimed to determine the impact of intense running in HR mice with wheel access on hippocampal LTP, compared to HR mice without wheels and non-selected control (C) mice with/without wheels. Additionally, we investigated the involvement of D1/D5 receptors and the dopamine transporter (DAT) in LTP modulation and examined levels of these proteins in HR and C mice. MethodsAdult female HR and C mice were individually housed with/without running wheels for at least two weeks. Hippocampal LTP of extracellular field excitatory postsynaptic potentials (fEPSPs) was measured in area CA1, and SKF-38393 (D1/D5 receptor agonist) and GBR 12909 (DAT inhibitor) were used to probe the role of D1/D5 receptors and DAT in LTP differences. Western blot analyses assessed D1/D5 receptor and DAT expression in the hippocampus, prefrontal cortex, and cerebellum. ResultsHR mice with wheel access showed significantly increased hippocampal LTP compared to those without wheels and to C mice with/without wheels. Treatment with SKF-38393 or GBR 12909 prevented the heightened LTP in HR mice with wheels, aligning it with levels in C mice. Hippocampal D1/D5 receptor levels were lower, and DAT levels were higher in HR mice compared to C mice. No significant changes were observed in other brain regions. ConclusionsThe increased hippocampal LTP seen in HR mice with wheel access may be related to alterations in dopaminergic synaptic transmission that underlie the neurophysiological basis of hyperactivity, motor disorders, and/or motivation.
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- Award ID(s):
- 2038528
- PAR ID:
- 10599406
- Publisher / Repository:
- Sage Publications
- Date Published:
- Journal Name:
- Restorative Neurology and Neuroscience
- ISSN:
- 0922-6028
- Subject(s) / Keyword(s):
- high-runner mice voluntary running long-term potentiation dopamine D1 receptors hippocampus
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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