The effects of ovariectomy on the behavioral and physiological responses to constant light in C57BL6/J Mice

Michaud, Julie M.; Price, John C.; Deane, Hannah V; Concepcion, Holly A.; Coronella, Jason A.; DeCourcey, Holly; Seggio, Joseph A.

doi:10.1080/09291016.2020.1842970

Cited by 5 publications

(6 citation statements)

References 74 publications

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“…In addition to abnormal responses to both chronic and acute light exposure, mice which underwent OVX without estradiol implantation exhibited significantly reduced rhythm cohesiveness and robustness (circadian power) and an increased likelihood of becoming arrhythmic by the end of the experiment compared with Sham controls and OVX animals with an estradiol pellet. These results are consistent with previously published work also showing that OVX leads to irregular behavioral rhythms and that estradiol replacement can rescue these abnormalities (Thomas and Armstrong, 1989; Michaud et al, 2022). Interestingly, these effects are once again relegated to LL—if the OVX animals are placed back into DD, they resume exhibiting a normal free-running rhythm with no differences in period length (Thomas and Armstrong, 1989).…”

Section: Discussionsupporting

confidence: 93%

“…Nevertheless, both androgen and estradiol treatment tend to shorten periods and cause an advance in activity onset in DD (Morin et al, 1977; Iwahana et al, 2008). which may also explain why gonadectomized animals (male or female) in LD or DD exhibit later activity onsets compared with estrogen and ER intact controls (Brockman et al, 2011; Blattner and Mahoney, 2014; Michaud et al, 2022, current study).…”

Section: Discussionmentioning

confidence: 78%

“…The SCN was visually identified using a dissecting microscope, by its location at the base of third ventricle and by locating the medial optic chiasm as a point of reference. SCN homogenates were created in a cocktail containing Pierce Lysis buffer and Halt protease inhibitor (Thermo Scientific, Rockford IL, USA), as previously described (Michaud et al, 2022). The supernatant was used in ERα (ESR1) (Mouse Estrogen Receptor Alpha—MBS776118) and ERβ (ESR2) (Mouse Estrogen Receptor Beta—MBS776119) ELISAs (MyBioSource).…”

Section: Methodsmentioning

confidence: 99%

“…Recent work from our lab has also shown that female mice which underwent OVX experience reduced circadian robustness and have an increased likelihood of becoming arrhythmic, independent of the reductions in overall activity levels (Michaud et al, 2022). However, as estradiol was not replaced after OVX in that study, it is not definitive that the estradiol itself mediated the effects of light exposure on circadian timing in those animals.…”

Section: Introductionmentioning

confidence: 99%

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Estradiol Regulates Circadian Responses to Acute and Constant Light Exposure in Female Mice

Michaud,

Waring,

Medeiros Contini

et al. 2023

J Biol Rhythms

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Sex hormones are well known to modulate circadian timekeeping as well as the behavioral and physiological responses to circadian disruption. Gonadectomy, reducing the amount of circulating gonadal hormones, in males and females produces alterations to the free-running rhythm and the responses to light exposure by the central oscillator of the suprachiasmatic nucleus (SCN). In this study, we tested whether estradiol plays a role in regulating the circadian responses to acute (light pulses) and chronic light exposure (constant light [LL] vs standard light:dark [LD] cycle) in female C57BL6/NJ mice. Mice were either ovariectomized or given sham surgery and given a placebo (P) or estradiol (E) pellet for hormone replacement so that there were 6 groups: (1) LD/Sham, (2) LL/Sham, (3) LD/OVX + P, (4) LL/OVX + P, (5) LD/OVX + E, and (6) LL/OVX + E. After 65 days of light cycle exposure, blood and SCNs were removed and serum estradiol plus SCN estradiol receptor alpha (ERα) and estradiol receptor beta (ERβ) were measured via ELISA. The OVX + P mice exhibited shorter circadian periods and were more likely to become arrhythmic in LL compared with mice with intact estradiol (sham or E replacement mice). The OVX + P mice exhibited reduced circadian robustness (power) and reduced circadian locomotor activity in both LD and LL compared with sham controls or OVX + E mice. The OVX + P mice also exhibited later activity onsets in LD and attenuated phase delays, but not advances, when given a 15-min light pulse compared with estradiol intact mice. LL led to reductions in ERβ, but not ERα, regardless of the surgery type. These results indicate that estradiol can modulate the effects of light on the circadian timing system and that estradiol can enhance responses to light exposure and provide protection against a loss of circadian robustness.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 78%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Estradiol Regulates Circadian Responses to Acute and Constant Light Exposure in Female Mice

Michaud,

Waring,

Medeiros Contini

et al. 2023

J Biol Rhythms

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“…Another observed effect of continuous light in goldfish was the increase in the fish mean swimming velocity in both performances of the OF task (i.e., days 3-4 and 46-47). Similarly, extended photoperiods have been shown to induce hyperactivity and greater distances moved in the OF and in the plus maze tests in rodent models [69,70] and to increase general locomotor activity in mice and fish [71][72][73][74]. However, some reports on rats have obtained different results in which LL did not increase ambulation in the OF test [65].…”

Section: Discussionmentioning

confidence: 99%

Assessing Chronodisruption Distress in Goldfish: The Importance of Multimodal Approaches

Saiz,

Herrera-Castillo,

de Pedro

et al. 2023

Animals

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Chronodisruption caused by factors such as light at night and mistimed meals has been linked to numerous physiological alterations in vertebrates and may be an anxiogenic factor affecting welfare. This study aims to investigate whether chronodisruption causes measurable changes in the anxiety responses of goldfish under two conditions: randomly scheduled feeding (RF) and continuous light (LL). Anxiety-like behavior was assessed in the open field with object approach and black/white preference tests, which had been validated using diazepam. An increased thigmotaxis response and decreased object exploration under both chronodisruption protocols indicated anxiety states. Furthermore, locomotor activity was increased in LL fish. The black/white preference test discriminated anxiolysis induced by diazepam but was unable to detect anxiety caused by chronodisruption. Plasma cortisol increased in both RF and LL fish throughout the experiment, confirming that both conditions caused stress. The LL fish also showed an apparently desensitized hypothalamus–pituitary–interrenal HPI axis, with a decrease in pomc and crf expression. Individual analysis found no correlation between anxiety-like behavior and stress axis activation nor between scototaxis and thigmotaxis responses. However, individual differences in sensitivity to each test were detected. Altogether, these results highlight circadian disruption as a stressor for fish and endorse a multiple variable approach for reliably assessing animal discomfort.

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Obesity alters circadian and behavioral responses to constant light in male mice

Burns,

Contini,

Michaud

et al. 2024

Physiology & Behavior

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The effects of ovariectomy on the behavioral and physiological responses to constant light in C57BL6/J Mice

Cited by 5 publications

References 74 publications

Estradiol Regulates Circadian Responses to Acute and Constant Light Exposure in Female Mice

Estradiol Regulates Circadian Responses to Acute and Constant Light Exposure in Female Mice

Assessing Chronodisruption Distress in Goldfish: The Importance of Multimodal Approaches

Obesity alters circadian and behavioral responses to constant light in male mice

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