Maintenance of Estrous Cycle in Female Rats with Anterior or Posterior Deafferentation of the Suprachiasmatic Nucleus

1988 ◽  
Vol 47 (5) ◽  
pp. 444-452 ◽  
Author(s):  
Kouji Nomura ◽  
Sumio Takahashi ◽  
Seiichiro Kawashima
Keyword(s):  
Estrous Cycle ◽  
Suprachiasmatic Nucleus ◽  
Female Rats

Shifts in preferred learning strategy across the estrous cycle in female rats

2004 ◽  
Vol 45 (5) ◽  
pp. 330-338 ◽  
Author(s):  
Donna L Korol ◽  
Emily L Malin ◽  
Kristine A Borden ◽  
Rachel A Busby ◽  
Julia Couper-Leo
Keyword(s):  
Estrous Cycle ◽  
Learning Strategy ◽  
Female Rats

The anorectic effect of fenfluramine is influenced by sex and stage of the estrous cycle in rats

2005 ◽  
Vol 288 (6) ◽  
pp. R1486-R1491 ◽  
Author(s):  
Lisa A. Eckel ◽  
Heidi M. Rivera ◽  
Deann P. D. Atchley
Keyword(s):  
Food Intake ◽  
Estrous Cycle ◽  
Female Rats ◽  
Male Rats ◽  
Gonadal Hormone ◽  
Estrous Female ◽  
Male And Female Rats ◽  
Daily Food ◽  
Hormone Status ◽  
Anorectic Effect

The controls of food intake differ in male and female rats. Daily food intake is typically greater in male rats, relative to female rats, and a decrease in food intake, coincident with the estrous stage of the ovarian reproductive cycle, is well documented in female rats. This estrous-related decrease in food intake has been attributed to a transient increase in the female rat's sensitivity to satiety signals generated during feeding bouts. Here, we investigated whether sex or stage of the estrous cycle modulate the satiety signal generated by fenfluramine, a potent serotonin (5-HT) releasing agent. To examine this hypothesis, food intake was monitored in male, diestrous female, and estrous female rats after intraperitoneal injections of 0, 0.25, and 1.0 mg/kg d-fenfluramine. The lower dose of fenfluramine decreased food intake only in diestrous and estrous females, suggesting that the minimally effective anorectic dose of fenfluramine is lower in female rats, relative to male rats. Although the larger dose of fenfluramine decreased food intake in both sexes, the duration of anorexia was greater in diestrous and estrous female rats, relative to male rats. Moreover, the magnitude of the anorectic effect of the larger dose of fenfluramine was greatest in estrous rats, intermediate in diestrous rats, and least in male rats. Thus our findings indicate that the anorectic effect of fenfluramine is modulated by gonadal hormone status.

063 — (ROD0183) Voltage oscillations induced by intrahippocampal pilocarpine in female rats during the estrous cycle

2014 ◽  
Vol 38 ◽  
pp. 208-209
Author(s):  
M.C.A. Rodrigues ◽  
A.R. Isaac ◽  
B.L.S. Andrade-da-Costa
Keyword(s):  
Estrous Cycle ◽  
Female Rats

Estrous cycle influence on individual differences in the response to novelty and cocaine in female rats

2005 ◽  
Vol 161 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Stacy L. Sell ◽  
Ashlee M. Dillon ◽  
Kathryn A. Cunningham ◽  
Mary L. Thomas
Keyword(s):  
Individual Differences ◽  
Estrous Cycle ◽  
Female Rats

Circadian and estrous cycle-dependent variations in blood pressure and heart rate in female rats

1994 ◽  
Vol 267 (5) ◽  
pp. R1250-R1256 ◽  
Author(s):  
H. Takezawa ◽  
H. Hayashi ◽  
H. Sano ◽  
H. Saito ◽  
S. Ebihara
Keyword(s):  
Heart Rate ◽  
Estrous Cycle ◽  
Female Rats ◽  
Constant Darkness ◽  
Dark Phase ◽  
Daily Rhythms ◽  
Abrupt Decrease ◽  
Internal Phase ◽  
Free Running ◽  
Cycle Dependent

To determine whether cardiovascular functions are controlled by the endogenous circadian system and whether they change with the estrous cycle in female rats, we measured mean arterial pressure (MAP), heart rate (HR), and spontaneous activity (ACT) of female rats using an implantable radiotelemetry device and a computerized data-collecting system. Under a 12:12-h light-dark (LD) cycle, these parameters exhibited daily rhythms that were entrained to the photic cycle. The patterns of the daily rhythms varied with estrous cycles, and variations were particularly marked in the proestrous stage. During the dark period of this stage, ACT levels were significantly higher, but HR was significantly lower than in other stages. Although the peak MAP occurred within 2 h after the onset of the dark phase in three of the estrous stages, it occurred around midnight in the proestrous stage. Such estrous cycle-dependent variations were eliminated by ovariectomy. The implantation of 17 beta-estradiol produced a gradual increase in MAP and an abrupt decrease in HR. During constant darkness, all three parameters were free running, maintaining the same internal phase relationships with each other as during LD cycles. These results indicate that daily variations in these parameters were controlled by the endogenous circadian oscillating system, that they vary with the estrous cycle in female rats, and that estrogen may be responsible for these estrous cycle-dependent variations.

scholarly journals Vasopressinergic Activity of the Suprachiasmatic Nucleus and mRNA Expression of Clock Genes in the Hypothalamus-Pituitary-Gonadal Axis in Female Aging

2021 ◽  
Vol 12 ◽  
Author(s):  
Angela Cristina Nicola ◽  
Larissa Brazoloto Ferreira ◽  
Milene Mantovani Mata ◽  
Tatiane Vilhena-Franco ◽  
Cristiane Mota Leite ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Feedback Loops ◽  
Female Rats ◽  
Hpg Axis ◽  
Physiological Processes ◽  
Reproductive Axis ◽  
Reproductive Events ◽  
Vasopressinergic Neurons

The important involvement of the suprachiasmatic nucleus (SCN) and the activity of vasopressinergic neurons in maintaining the rhythmicity of the female reproductive system depends on the mRNA transcription-translation feedback loops. Therefore, circadian clock function, like most physiological processes, is involved in the events that determine reproductive aging. This study describes the change of mRNA expression of clock genes, Per2, Bmal1, and Rev-erbα, in the hypothalamus-pituitary-gonadal axis (HPG) of female rats with regular cycle (RC) and irregular cycle (IC), and the vasopressinergic neurons activity in the SCN and kisspeptin neurons in the arcuate nucleus (ARC) of these animals. Results for gonadotropins and the cFos/AVP-ir neurons in the SCN of IC were higher, but kisspeptin-ir was minor. Change in the temporal synchrony of the clock system in the HPG axis, during the period prior to the cessation of ovulatory cycles, was identified. The analysis of mRNA for Per2, Bmal1, and Rev-erbα in the reproductive axis of adult female rodents shows that the regularity of the estrous cycle is guaranteed by alternation in the amount of expression of Bmal1 and Per2, and Rev-erbα and Bmal1 between light and dark phases, which ceases to occur and contributes to determining reproductive senescence. These results showed that the desynchronization between the central and peripheral circadian clocks contributes to the irregularity of reproductive events. We suggest that the feedback loops of clock genes on the HPG axis modulate the spontaneous transition from regular to irregular cycle and to acyclicity in female rodents.

scholarly journals Subchronic Exposure to Cadmium Causes Persistent Changes in the Reproductive System in Female Wistar Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Marzenna Nasiadek ◽  
Marian Danilewicz ◽  
Michał Klimczak ◽  
Joanna Stragierowicz ◽  
Anna Kilanowicz
Keyword(s):  
Lipid Peroxidation ◽  
Estrous Cycle ◽  
Structural Damage ◽  
Female Rats ◽  
Uterine Tissue ◽  
Female Wistar Rats ◽  
Epithelium Thickness ◽  
Endometrial Epithelium ◽  
Positive Correlations ◽  
Cd Exposure

Cadmium (Cd) is an environmental toxicant and endocrine disruptor in humans and animals, and recent studies have illustrated that the uterus is exceedingly sensitive to Cd toxicity. The aim of the study was to investigate the influence of subchronic (90 days) oral Cd exposure in daily doses of 0.09-4.5 mg/kg b.w. on the balance of sex hormones by estimating estradiol (E2) and progesterone (P) concentrations in the uterus and plasma in comparison with the effects of 17β-E2. Additionally, the uterine weight, histopathological changes in the uterus and ovaries, the regularity of the estrous cycle, Cd bioaccumulation in uterine tissue, and selected biochemical parameters of oxidative stress were determined. A long period of observation (three and six months following the administration period) was used to assess whether the existing effects are reversible. The lowest dose of Cd caused effects similar to 17β-E2: an increase of E2 concentration in the uterus, endometrial epithelium thickness, and disturbed estrous cycle with estrus phase prolongation. The obtained results suggest that Cd causes nonlinear response. Higher doses of Cd caused a significant decrease in E2 concentration in the uterus and plasma, estrous cycle disturbances, endometrium atrophy, and structural damage in the ovaries. This dose additionally induces lipid peroxidation in the uterine tissues. It is noteworthy that a prolonged time of observation after terminating the exposure showed persistent changes in the concentration of E2 in uterine tissue, as well as alterations in estrous cycle phases, and an increase in lipid peroxidation in the uterus. Moreover, significant positive correlations between the plasma E2 concentration and endometrial epithelium thickness in all studied groups were found. In summary, subchronic oral Cd exposure of female rats may result in impaired fertility processes.

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