Physical weight loading induces expression of tryptophan hydroxylase 2 in the brain stem

Joon W. Shim, Todd R. Dodge, Max A. Hammond, Joseph M. Wallace, Feng Zhou, Hiroki Yokota

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Sustaining brain serotonin is essential in mental health. Physical activities can attenuate mental problems by enhancing serotonin signaling. However, such activity is not always possible in disabled individuals or patients with dementia. Knee loading, a form of physical activity, has been found to mimic effects of voluntary exercise. Focusing on serotonergic signaling, we addressed a question: Does local mechanical loading to the skeleton elevate expression of tryptophan hydroxylase 2 (tph2) that is a rate-limiting enzyme for brain serotonin? A 5 min knee loading was applied to mice using 1 N force at 5 Hz for 1,500 cycles. A 5-min treadmill running was used as an exercise (positive) control, and a 90-min tail suspension was used as a stress (negative) control. Expression of tph2 was determined 30 min - 2 h in three brain regions - frontal cortex (FC), ventromedial hypothalamus (VMH), and brain stem (BS). We demonstrated for the first time that knee loading and treadmill exercise upregulated the mRNA level of tph2 in the BS, while tail suspension downregulated it. The protein level of tph2 in the BS was also upregulated by knee loading and downregulated by tail suspension. Furthermore, the downregulation of tph2 mRNA by tail suspension can be partially suppressed by pre-application of knee loading. The expression of tph2 in the FC and VMH was not significantly altered with knee loading. In this study we provided evidence that peripheral mechanical loading can activate central tph2 expression, suggesting that physical cues may mediate tph2- cathalyzed serotonergic signaling in the brain.

Original languageEnglish
Article numbere85095
JournalPLoS One
Volume9
Issue number1
DOIs
StatePublished - Jan 8 2014

Fingerprint

Tryptophan Hydroxylase
brain stem
tryptophan
Brain Stem
knees
Brain
Hindlimb Suspension
Weights and Measures
Knee
Exercise
Suspensions
tail
serotonin
brain
Serotonin
Exercise equipment
exercise
Down-Regulation
exercise equipment
Frontal Lobe

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Shim, J. W., Dodge, T. R., Hammond, M. A., Wallace, J. M., Zhou, F., & Yokota, H. (2014). Physical weight loading induces expression of tryptophan hydroxylase 2 in the brain stem. PLoS One, 9(1), [e85095]. https://doi.org/10.1371/journal.pone.0085095

Physical weight loading induces expression of tryptophan hydroxylase 2 in the brain stem. / Shim, Joon W.; Dodge, Todd R.; Hammond, Max A.; Wallace, Joseph M.; Zhou, Feng; Yokota, Hiroki.

In: PLoS One, Vol. 9, No. 1, e85095, 08.01.2014.

Research output: Contribution to journalArticle

Shim, Joon W. ; Dodge, Todd R. ; Hammond, Max A. ; Wallace, Joseph M. ; Zhou, Feng ; Yokota, Hiroki. / Physical weight loading induces expression of tryptophan hydroxylase 2 in the brain stem. In: PLoS One. 2014 ; Vol. 9, No. 1.
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