Pregnancy-induced changes in ultradian rhythms persist in circadian arrhythmic Siberian hamsters

Abstract

The impact of pregnancy and lactation on ultradian rhythms (URs) and circadian rhythms (CRs) of locomotor activity was assessed in circadian rhythmic and arrhythmic Siberian hamsters maintained in a long-day photoperiod (16 h light/day). Progressive decrements in CR robustness and amplitude over the course of gestation were accompanied by enhanced URs. Dark-phase UR period and amplitude increased during early gestation and complexity and robustness increased during late gestation. The persistence of pregnancy-associated enhancements of URs in circadian arrhythmic (ARR) hamsters suggests that reproductive modulation of the UR waveform is not dependent on coherent circadian organization. The increased incidence of dark-phase URs appeared more rapidly in ARR dams than entrained (ENTR) dams. Throughout gestation, the percentage of dams with dark-phase URs was significantly greater in the ARR group. Gestational increases in UR complexity and robustness emerged earlier and were greater in ARR than ENTR dams. The attenuation of CRs during lactation is correlated with increased expression of URs. Relaxation of circadian control of the dam's behavior may increase fitness by permitting more efficient interactions with circadian arrhythmic pups.

Modified Wavelet Analyses Permit Quantification of Dynamic Interactions Between Ultradian and Circadian Rhythms

“…This analytic approach was applied to quantify changes in URs in response to genomic, environmental, and endocrine factors previously reported to modulate the ultradian waveform. Consistent with observations in numerous and diverse species (Wollnik and Dohler, 1986;Wollnik and Turek, 1988;Heldmaier et al, 1989;Siebert and Wollnik, 1991;Hagenauer et al, 2011;Prendergast et al, 2012b;Prendergast and Zucker, 2012;Prendergast et al, 2013;Wang et al, 2014;Smarr et al, 2019), C57BL6/J mice exhibited multiple sex differences in UR power structure and period under a 12 L:12D photocycle. In the active phase, UR power was more prominently distributed across shorter periods in males, and among longer periods in females, whereas in the light phase UR power structure was largely indistinguishable between the sexes.…”

Maternal and Early-Life Circadian Disruption Have Long-Lasting Negative Consequences on Offspring Development and Adult Behavior in Mice

“…Importantly, temporal structure governing behavior in the mother, and likely in the fetus, is provided by ultradian (rhythms < 24 h) as well as circadian mechanisms. Several physiological systems exhibit ultradian rhythms (URs) in the 1–3 h range, including the HPG axis 60 – 65 , the HPA axis 66 – 72 , and the suprachiasmatic nucleus 73 , 74 – the principal orchestrating brain area for circadian rhythms. The central dopaminergic axis exhibits URs in the 1–3 h range 75 , and may influence CBT as well through modulation of activity and appetitive behaviors, such as eating and drinking (reviewed in ref.…”

Sex Differences in Pubertal Circadian and Ultradian Rhythmic Development Under Naturalistic Conditions

“…Peripheral measurements of temperature, such as those from the iButton (Hasselberg et al, 2013) or Oura Ring (Grant et al, 2020;Maijala et al, 2019), could be sufficient for peripubertal detection of temperature and ultradian power rises (Grant et al, 2020), and could be used to develop a population-wide database characterizing features associated with pubertal onset and development. Indeed, rhythmic features of body temperature have already formed the basis of methods for monitoring reproductive health, including pubertal onset and contraceptive use in a laboratory setting , adult fertility in controlled and real world conditions (Grant et al, 2020;Prendergast et al, 2012;Sanchez-Alavez et al, 2011;Smarr et al, 2017), and pregnancy in the laboratory and in small, retrospective cohorts Smarr et al, 2016;Wang et al, 2014). Such tools could be informative and empowering to young people during puberty, potentially anticipating first onset of menses (Fowler et al, 2020;Wartella et al, 2016), impending growth spurts, or for identifying adverse reactions to disruptive behavior (Asimes et al, 2018;Logan et al, 2018) and medication (Apter, 2018).…”

“…Indeed, rhythmic features of body temperature have already formed the basis of methods for monitoring reproductive health, including pubertal onset(Grant et al, 2021) and contraceptive use in a laboratory setting(Grant et al, 2021), adult fertility in controlled and real world conditions(Grant et al, 2020; Prendergast et al, 2012; Sanchez-Alavez et al, 2011; Smarr et al, 2017), and pregnancy in the laboratory and in small, retrospective cohorts(Grant et al, 2021. ; Smarr et al, 2016; Wang et al, 2014). Such tools could be informative and empowering to young people during puberty, potentially anticipating first onset of menses(Fowler et al, 2020; Wartella et al, 2016), impending growth spurts, or for identifying adverse reactions to disruptive behavior(Asimes et al, 2018; Logan et al, 2018) and medication(Apter, 2018).…”