A review of the current state of knowledge on sex differences in sleep and circadian phenotypes in rodents

Abstract

Sleep is a vital part of our lives as it is required to maintain health and optimal cognition. In humans, sex differences are relatively well-established for many sleep phenotypes. However, precise differences in sleep phenotypes between male and female rodents are less documented. The main goal of this article is to review sex differences in sleep architecture and electroencephalographic (EEG) activity during wakefulness and sleep in rodents. The effects of acute sleep deprivation on sleep duration and EEG activity in male and female rodents will also be covered, in addition to sex differences in specific circadian phenotypes. When possible, the contribution of the female estrous cycle to the observed differences between males and females will be described. In general, male rodents spend more time in non-rapid eye movement sleep (NREMS) in comparison to females, while other differences between sexes in sleep phenotypes are species- and estrous cycle phase-dependent. Altogether, the review illustrates the need for a sex-based perspective in basic sleep and circadian research, including the consideration of sex chromosomes and gonadal hormones in sleep and circadian phenotypes.

Changes in striatal dopamine release, sleep, and behavior during spontaneous Δ-9-tetrahydrocannabinol abstinence in male and female mice

“…In several of our assays, female data appear more variable than males. This could be due to influences of sex-hormone cycling, which are known to influence sleep [ 97 ] and motivated behaviors [ 98 ]. Likewise, THC is lipophilic and can be stored in adipose tissue [ 99 ].…”

Striatal-Inoculation of α-Synuclein Preformed Fibrils Aggravated the Phenotypes of REM Sleep without Atonia in A53T BAC-SNCA Transgenic Mice

“…Fourth, we only used male mice for sleep analysis in the present study since RBD is generally more common in males than in females. The previous study analyzing WT mice inoculated with α-syn PFFs into the CNS reported that male PFFs-injected mice developed more severe α-syn pathology than female ones [ 19 ], while there was no significant difference in REM sleep amounts between the sexes [ 20 ]. Future research should be done on both sexes to understand the disease in future studies.…”

IL-6 deletion decreased REV-ERBα protein and influenced autophagy and mitochondrial markers in the skeletal muscle after acute exercise

“…For the IL-6 knockout (KO) group, eight-week-old IL-6 -/- male mice from the Laboratory of Molecular Immunology and Embryology, Transgenose Institute, Centre National de la Recherche Scientifique (CNRS) were bred onto a C57BL/6 background and used for the other experimental group. The male gender was used to avoid the influence of the hormonal cycle of female mice since the responses of the circadian cycle can suffer interference ( 17 ). The Ethics Committee of the University of Sao Paulo (I.D.…”