Elsevier

Behavioural Brain Research

Volume 197, Issue 2, 11 February 2009, Pages 450-453
Behavioural Brain Research

Short communication
Experimental sleep fragmentation and sleep deprivation in rats increases exploration in an open field test of anxiety while increasing plasma corticosterone levels

https://doi.org/10.1016/j.bbr.2008.08.035Get rights and content

Abstract

Sleep deprivation alters mood and anxiety in man. In rats, 24 h of treadmill-induced total sleep deprivation or sleep fragmentation increased exploratory behavior in an open field test of anxiety compared to cage or exercise controls. Plasma corticosterone (CORT) levels of sleep disturbed and exercise control rats were elevated compared to cage controls, suggesting that the increased exploration observed in the sleep disturbed rats was not due to a hypothalamic–pituitary–adrenal (HPA) stress response.

Section snippets

Open field test of anxiety

Fig. 1 illustrates the rodents’ behaviors in the open field task. As shown in Fig. 1A, the disruption of sleep in rats resulted in a significant change in the percent time spent in the open field (F(3,24) = 8.599, p < 0.001) so that when compared to exercise control rats (n = 8), rats spent significantly more time in the open space in both the 24 h total sleep deprivation (n = 6, Fisher’s, p = 0.002) and 24 h sleep fragmentation (n = 7, p < 0.001) groups. The same relationship was seen when cage controls (n = 7)

Plasma corticosterone

Plasma CORT levels in rats undergoing 24 h of sleep fragmentation, sleep deprivation, and exercise control were highly variable and failed to meet the statistical assumption of homogeneity of variance (Levene = 6.556, p = .003). Therefore, the nonparametric Kruskal–Wallis test was utilized to analyze the CORT data. As can be seen in Fig. 2, an overall significant main effect of treatment was observed for all manipulations (χ2 = 12.826, p = 0.005) and a follow up with chi-square analysis indicated that

Acknowledgements

We thank John Franco for care of the animals. This research was supported by: Department of Veterans Affairs Medical Research Service Award to R.E.S., NHLBI – P50 HL060292 (R.E.S. and R.W.M.), NHLBI – T32 HL07901 (J.L.T.).

Disclosure statement: This is not an industry supported study. The authors have indicated no financial conflicts of interest.

Author contributions: J.L.T. designed and conducted the experiment, analyzed data and wrote the paper; J.W.C., S.L.G. and A.J.B. assisted in conducting

References (30)

  • Z.J. van Hulzen et al.

    Paradoxical sleep deprivation and locomotor activity in rats

    Physiol Behav

    (1981)
  • I. Albert et al.

    The behavioral effects of REM sleep deprivation in rats

    Psychophysiology

    (1970)
  • H.C. Atkinson et al.

    Diurnal variation in the responsiveness of the hypothalamic–pituitary–adrenal axis of the male rat to noise stress

    J Neuroendocrinol

    (1970)
  • M.H. Bonnet

    Effect of sleep disruption on sleep, performance, and mood

    Sleep

    (1985)
  • M.H. Bonnet et al.

    Metabolism during normal, fragmented, and recovery sleep

    J Appl Physiol

    (1992)
  • Cited by (81)

    View all citing articles on Scopus
    View full text