Changing patterns of daily rhythmicity across reproductive states in diurnal female Nile grass rats (Arvicanthis niloticus)

Schrader, Jessica A.; Walaszczyk, Erin J.; Smale, Laura

doi:10.1016/j.physbeh.2009.08.012

Cited by 21 publications

(13 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In CTR cows, a significant increase in core body temperature amplitude and mesor occurred between 3 and 1 wk BEC. The increase in mesor was likely related to thermogenesis associated with the progression of pregnancy and fetal growth (Schrader et al, 2009;Gamo et al, 2013). Similar to CTR cows, mesor of core body temperature of PS cows increased from 23 to 9 d BEC.…”

Section: Circadian Disruption Changed Rhythms Of Body Temperature Mementioning

confidence: 79%

Exposure to chronic light–dark phase shifts during the prepartum nonlactating period attenuates circadian rhythms, decreases blood glucose, and increases milk yield in the subsequent lactation

Suárez-Trujillo

Wernert

Sun

et al. 2020

Journal of Dairy Science

View full text Add to dashboard Cite

Maintaining metabolic balance is a key factor in the health of dairy cattle during the transition from pregnancy to lactation. Little is known regarding the role of the circadian timing system in the regulation of physiological changes during the transition period. We hypothesized that disruption of the cow's circadian timing system by exposure to chronic light-dark phase shifts during the prepartum period would negatively affect the regulation of homeostasis and cause metabolic disturbances, leading to reduced milk production in the subsequent lactation. The objective was to determine the effect of exposure to chronic light-dark phase shift during the last 5 wk prepartum of the nonlactating dry period on core body temperature, melatonin, blood glucose, β-hydroxybutyric acid (BHB) and nonesterified fatty acid (NEFA) concentrations, and milk production. Multiparous cows were moved to tiestalls at 5 wk before expected calving and assigned to control (CTR; n = 16) or phase-shifted (PS; n = 16) treatments. Control cows were exposed to 16 h of light and 8 h of dark. Phase-shifted cows were exposed to the same photoperiod; however, the light-dark cycle was shifted 6 h every 3 d until parturition. Resting behavior and feed intake were recorded daily. Core body temperature was recorded vaginally for 48 h at 23 and 9 d before expected calving using calibrated data loggers. Blood concentrations of melatonin, glucose, BHB, and NEFA were measured during the pre-and postpartum periods. Milk yield and composition were measured through 60 DIM. Treatment did not affect feed intake or body condition. Cosine fit analysis of 24-h core body temperature and circulating melatonin indicated attenuation of circadian rhythms in the PS treatment compared with the CTR treatment. Phase-shifted cows had lower rest consolidation, as indicated by more total resting time, but shorter resting period durations. Phase-shifted cows had lower blood glucose concentration compared with CTR cows (4 mg/mL decrease), but BHB and NEFA concentrations were similar between PS and CTR cows. Milk yield and milk fat yield were greater in PS compared with CTR cows (2.8 kg/d increase). Thus, exposure to chronic light-dark phase shifts during the prepartum period attenuated circadian rhythms of core body temperature, melatonin, and rest-activity behavior and was associated with increased milk fat and milk yield in the postpartum period despite decreased blood glucose pre-and postpartum. Therefore, less variation in central circadian rhythms may create a more constant milieu that supports the onset of lactogenesis.

show abstract

Section: Circadian Disruption Changed Rhythms Of Body Temperature Mementioning

confidence: 79%

Exposure to chronic light–dark phase shifts during the prepartum nonlactating period attenuates circadian rhythms, decreases blood glucose, and increases milk yield in the subsequent lactation

Suárez-Trujillo

Wernert

Sun

et al. 2020

Journal of Dairy Science

View full text Add to dashboard Cite

show abstract

“…Yet a significant rhythm is still present. The diurnal Nile grass rat also exhibits a circadian rhythm in activity during lactation which is even greater than that of virgin females but less than that of pregnant females [ 88 ]. Although we expected a dampening of the difference in cage activity between the light and dark periods in lactating mice, due to time spent nursing in the nest, we were surprised at the total absence of a rhythm.…”

Section: Discussionmentioning

confidence: 99%

Enhanced Responsiveness to Selective Serotonin Reuptake Inhibitors during Lactation

et al. 2015

View full text Add to dashboard Cite

The physiology of mood regulation in the postpartum is poorly understood despite the fact that postpartum depression (PPD) is a common pathology. Serotonergic mechanisms and their dysfunction are widely presumed to be involved, which has led us to investigate whether lactation induces changes in central or peripheral serotonin (5-HT) systems and related affective behaviors. Brain sections from lactating (day 10 postpartum) and age-matched nulliparous (non-pregnant) C57BL/6J mice were processed for 5-HT immunohistochemistry. The total number of 5-HT immunostained cells and optical density were measured. Lactating mice exhibited lower immunoreactive 5-HT and intensity in the dorsal raphe nucleus when compared with nulliparous controls. Serum 5-HT was quantified from lactating and nulliparous mice using radioimmunoassay. Serum 5-HT concentrations were higher in lactating mice than in nulliparous controls. Affective behavior was assessed in lactating and non-lactating females ten days postpartum, as well as in nulliparous controls using the forced swim test (FST) and marble burying task (MBT). Animals were treated for the preceding five days with a selective serotonin reuptake inhibitor (SSRI, citalopram, 5mg/kg/day) or vehicle. Lactating mice exhibited a lower baseline immobility time during the FST and buried fewer marbles during the MBT as compared to nulliparous controls. Citalopram treatment changed these behaviors in lactating mice with further reductions in immobility during the FST and decreased marble burying. In contrast, the same regimen of citalopram treatment had no effect on these behaviors in either non-lactating postpartum or nulliparous females. Our findings demonstrate changes in both central and peripheral 5-HT systems associated with lactation, independent of pregnancy. They also demonstrate a significant interaction of lactation and responsiveness to SSRI treatment, which has important implications in the treatment of PPD. Although recent evidence has cast doubt on the effectiveness of SSRIs, these results support their therapeutic use in the treatment of PPD.

show abstract

“…Alpha was defined as the interval from the onset of the early morning bout to the offset of the evening bout. Onset and offset were identified as described previously [29], by using the Clocklab program (Actimetrics, Wilmette, IL; version 2.6.1) in conjunction with visual inspection of double plotted actograms. Two-way ANOVAs were performed separately for the data on alpha and period using 2×2 factorial designs [lighting condition (DD vs. LL; within-group factor) x surgical condition (sham vs. IGL lesion; between-group factor)].…”

Section: Methodsmentioning

confidence: 99%

Lesions of the Intergeniculate Leaflet Lead to a Reorganization in Circadian Regulation and a Reversal in Masking Responses to Photic Stimuli in the Nile Grass Rat

et al. 2013

Self Cite

View full text Add to dashboard Cite

Light influences the daily patterning of behavior by entraining circadian rhythms and through its acute effects on activity levels (masking). Mechanisms of entrainment are quite similar across species, but masking can be very different. Specifically, in diurnal species, light generally increases locomotor activity (positive masking), and in nocturnal ones, it generally suppresses it (negative masking). The intergeniculate leaflet (IGL), a subdivision of the lateral geniculate complex, receives direct retinal input and is reciprocally connected with the primary circadian clock, the suprachiasmatic nucleus (SCN). Here, we evaluated the influence of the IGL on masking and the circadian system in a diurnal rodent, the Nile grass rat (Arvicanthis niloticus), by determining the effects of bilateral IGL lesions on general activity under different lighting conditions. To examine masking responses, light or dark pulses were delivered in the dark or light phase, respectively. Light pulses at Zeitgeber time (ZT) 14 increased activity in control animals but decreased it in animals with IGL lesions. Dark pulses had no effect on controls, but significantly increased activity in lesioned animals at ZT0. Lesions also significantly increased activity, primarily during the dark phase of a 12:12 light/dark cycle, and during the subjective night when animals were kept in constant conditions. Taken together, our results suggest that the IGL plays a vital role in the maintenance of both the species-typical masking responses to light, and the circadian contribution to diurnality in grass rats.

show abstract

Changing patterns of daily rhythmicity across reproductive states in diurnal female Nile grass rats (Arvicanthis niloticus)

Cited by 21 publications

References 41 publications

Exposure to chronic light–dark phase shifts during the prepartum nonlactating period attenuates circadian rhythms, decreases blood glucose, and increases milk yield in the subsequent lactation

Exposure to chronic light–dark phase shifts during the prepartum nonlactating period attenuates circadian rhythms, decreases blood glucose, and increases milk yield in the subsequent lactation

Enhanced Responsiveness to Selective Serotonin Reuptake Inhibitors during Lactation

Lesions of the Intergeniculate Leaflet Lead to a Reorganization in Circadian Regulation and a Reversal in Masking Responses to Photic Stimuli in the Nile Grass Rat

Contact Info

Product

Resources

About