Changes in sleep-wakefulness in female rats during circadian and estrous cycles

Jinnai

et al. 1990

Stroke

We measured local cerebral blood flow over 24 hours in 10 unanesthetized, freely moving rats to determine whether blood flow in the hippocampus fluctuated as a function of time of day. We measured hydrogen clearance at 1-hour intervals using a polyurethane-coated platinum electrode with a 1-mm bare tip implanted in the dorsal hippocampus. Individual rats displayed a wide range of local cerebral blood flow values (from 30 to 100 ml/min/100 g tissue) in a day. In seven of the 10 rats, the overall mean hippocampal blood flow for the dark cycle (7 PM-5 AM) was significantly (p<0.001, 0.01, or 0.05) greater than that for the light cycle (6 AM-6 PM), showing an average increase of 20%. Further, the maximum mean hippocampal blood flow at 11 PM in all 10 rats was 42% greater than the minimum at noon. Our study demonstrates for the first time that local cerebral blood flow in the hippocampus shows diurnal variation. (Stroke

Section: Discussionmentioning

confidence: 58%

Diurnal variation of cerebral blood flow in rat hippocampus.

Jinnai

et al. 1990

Stroke

“…The brain temperature conforms well with this activity rhythm, confirming results of an earlier study which showed that gross changes in brain temperature of up to 1.5 °C/10 min can occur if the rat becomes active [Kleinlogel, 1977], Wheras active waking was highest at the beginning of darkness, SWS, but not PS, was highest at the beginning of the light period. During the day SWS decreased, whereas PS increased, a pattern which has also been described for rats and for humans in their inactive phase [Colvin et al, 1968;Feinberg, 1976;Borbely, 1982], The decrease of SWS was accompanied by an increase in the spindle phases, which followed the course of PS. Inspec tion of the Hjorth parameters shows that EEG desynch ronisation steadily increased during daytime sleep.…”

Section: Ultradian Vigilance Patternmentioning

confidence: 82%

“…However, even in this case SWS was increased on the following day. Colvin et al [1968], who recorded the rats' EEGs continuously throughout their oestrous cycles, also observed comparable changes of the circadian vigilance pattern. However, they distin guished only 3 states: waking, PS and the rest, and this may be the reason why they failed to observe a SWS increase on the day after the oestrous night.…”

Section: Circadian and Infradian Vigilance Patternmentioning

confidence: 93%

“…1), results which correspond with those of Yokoyama et al [1966], These findings raised the question of whether these phenomena in oestrus were rebound effects from the oestrous night, when the rat might have been more active, looking for a sexual partner. Colvin et al [1968] have shown that under 14 h light and 10 h dark condi tions, the night between prooestrus and oestrus is charac terized by alertness and virtual absence of PS. We have recently developed a method for continuous EEG record ing in the rat which enables us to record the EEG throughout the day-night cycle [Kleinlogel and Hausammann, 1980].…”

mentioning

confidence: 99%

See 1 more Smart Citation

The Female Rat’s Sleep during Oestrous Cycle

Kleinlogel¹

1983

Neuropsychobiology

The sleep-waking pattern of the isolated female rat showed a clear ultra-, circa- and infradian vigilance rhythm. The ultradian period was about 4–6 h. During the day, the amount of slow wave sleep (SWS) decreased and that of paradoxical sleep (PS) increased. In general, desynchronisation of the EEG increased during the day. The circadian period was determined by the light-dark cycle. Although the rats slept mainly during their inactive light phase, there was a considerable amount of sleep at night. The infradian period was determined by the individual length of the oestrous cycle. During the oestrous night more motor activity and less sleep was seen. During the following day a strong rebound of waking, SWS and PS occurred, but not of the ‘connecting’ sleep phases dozing and PS spindles. During the oestrous night the strong stimulation of the rat masked the ultradian rhythm. All oestrous effects disappeared in castrated female rats, which, compared to intact rats, showed more dozing during the night and the day as well as more PS during the hours of darkness.

“…Normal sleep patterns in the female rat are exquisitely sensitive to the natural fluctuations of ovarian steroids (for review see [1]). Findings from a number of studies in rats generally agree that on the night of pro-estrus, when oestradiol and progesterone are elevated, both NREMS and REMS are significantly reduced compared with other phases of the oestrous cycle [115][116][117][118]. Ovariectomy eliminates the fluctuations in nocturnal sleep observed over the oestrous cycle, and exogenous oestradiol plus progesterone or oestradiol alone are sufficient to recapitulate the suppression of sleep observed during the night of proestrus [108,[119][120][121][122].…”

Section: (A) Sex Differences In Sleep Behaviourmentioning

confidence: 99%

Sex differences in sleep: impact of biological sex and sex steroids

Mong

Cusmano

2016

Phil. Trans. R. Soc. B

400

300

One contribution of 16 to a theme issue 'Multifaceted origins of sex differences in the brain'. Men and women sleep differently. While much is known about the mechanisms that drive sleep, the reason for these sex differences in sleep behaviour is unknown and understudied. Historically, women and female animals are underrepresented in studies of sleep and its disorders. Nevertheless, there is a growing recognition of sex disparities in sleep and rhythm disorders. Women typically report poorer quality and more disrupted sleep across various stages of life. Findings from clinical and basic research studies strongly implicate a role for sex steroids in sleep modulation. Understanding how neuroendocrine mediators and sex differences influence sleep is central to advancing our understanding of sleep-related disorders. The investigation into sex differences and sex steroid modulation of sleep is in its infancy. Identifying the mechanisms underlying sex and gender differences in sleep will provide valuable insights leading to tailored therapeutics that benefit each sex. The goal of this review is to discuss our current understanding of how biological sex and sex steroids influence sleep behaviour from both the clinical and pre-clinical perspective.