Oxytocin secretion induced by osmotic stimulation in rats during the estrous cycle and after ovariectomy and hormone replacement therapy

Caligioni, Claudia S.; Franci, C.R.

doi:10.1016/s0024-3205(02)02139-2

Cited by 23 publications

(26 citation statements)

References 48 publications

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“…The estrogen treatment did not change this response. Previous reports had also shown a similar response of estrogen (Caligioni & Franci 2002, Hartley et al 2004. Plasma OT levels in all groups were higher than previously reported values because we did collect the blood under anesthesia.…”

Section: Discussionsupporting

confidence: 49%

“…Also, urinary output and urinary sodium excretion are decreased in estrous compared to diestrus (Forsling & Peysner 1988). It is known that physiological concentrations of estrogen stimulate the release of OT by the dendrites of magnocellular neurones in the SON (Wang et al 1995), and studies in our laboratory have shown that the secretion of OT varies during the estrous cycle, increasing during pro-estrous and the morning of estrous (Caligioni & Franci 2002). In addition, several studies have shown that estrogen may regulate many aspects of the function of OT neurones, including the expression of OT mRNA (Shughrue et al 2002), peptide synthesis (Levin & Sawchenko 1993), electrical activity (Negoro et al 1973) and the release of OT (Skowsky et al 1979).…”

Section: Discussionmentioning

confidence: 86%

“…Previous studies suggest that estrogen directly regulates the gene expression of OT in the PVN and the SON through ER-b (Shughrue et al 1996, Laflamme et al 1998, Hrabovszky et al 2004. Thus, estrogen increases the level of OT mRNA in neurones of the PVN and SON (Chung et al 1991, Amico et al 1995 and increases plasma OT levels (Amico et al 1981, Wang et al 1995, Caligioni & Franci 2002. The expression of ER-b in OT neurones is well established in the literature for the PVN, but has not been observed in the SON (Shughrue et al 1996, Alves et al 1998, Hrabovszky et al 1998, Laflamme et al 1998, Suzuki & Handa 2005.…”

Section: Discussionmentioning

confidence: 98%

“…An increase in plasma osmolality causes a rise in plasma OT levels that, in turn, induces the excretion of sodium and chloride (Balment et al 1980, Caligioni & Franci 2002.…”

Section: Introductionmentioning

confidence: 99%

“…Although the initial focus of OT research was on its role in reproduction, its role in hydroelectrolytic control is also under investigation now (Jones & Pickering 1969, Balment et al 1980, Caligioni & Franci 2002. There are several pieces of evidence indicating that gonadal steroids regulate the function of OT neurones.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Lucio-Oliveira¹,

Franci²

2011

Journal of Endocrinology

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Increased plasma osmolality by food intake evokes augmentation of plasma oxytocin (OT). Ovarian steroids may also influence the balance of body fluids by acting on OT neurones. Our aim was to determine if estrogen influences the activity of OT neurones in paraventricular nucleus (PVN) and supraoptic nucleus (SON) under different osmotic situations. Ovariectomized rats (OVX) were treated with either estradiol (E 2 ) or vehicle and were divided into three groups: group I was fed ad libitum, group II underwent 48 h of fasting, and group III was refed after 48 h of fasting. On the day of the experiment, blood samples were collected to determine the plasma osmolality and OT. The animals were subsequently perfused, and OT/FOS immunofluorescence analysis was conducted on neurones in the PVN and the SON. When compared to animals which were fasted or fed ad libitum, the plasma osmolality of refed animals was higher, regardless of whether they were treated with vehicle or E 2 . We observed neural activation of OT cells in vehicle-or E 2 -treated OVX rats refed after 48 h of fasting, but not in animals fed ad libitum or in animals that only underwent 48 h of fasting. Finally, the percentage of neurones that co-expressed OT and FOS was lower in both the PVN and the SON of animals treated with E 2 and refed, when compared to vehicle-treated animals. These results suggest that E 2 may have an inhibitory effect on OT neurones and may modulate the secretion of OT in response to the increase of osmolality induced by refeeding.

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Section: Discussionsupporting

confidence: 49%

Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 98%

“…An increase in plasma osmolality causes a rise in plasma OT levels that, in turn, induces the excretion of sodium and chloride (Balment et al 1980, Caligioni & Franci 2002.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Lucio-Oliveira¹,

Franci²

2011

Journal of Endocrinology

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Assessing Reproductive Status/Stages in Mice

2009

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The short reproductive cycle length observed in rodents, called the estrous cycle, makes them an ideal animal model for investigation of changes that occur during the reproductive cycle. Most of the data in the literature about the estrous cycle is obtained from rat because they are easily manipulated and exhibit a clear and well defined estrous cycle. However, the increased number of experiments using knockout mice requires identification of their estrous cycle as well, since (in)fertility issues may arise. In mice, like rats, the identification of the stage of estrous cycle is based on the proportion of cells types observed in the vaginal secretion. The aim of this unit is to provide guidelines for quickly and accurately determining estrous cycle phases in mice. Key terms for indexing Estrous cycle; mouse; vaginal smears; wet vaginalIn humans, the reproductive cycle, called the menstrual cycle, lasts approximately 28 days, in rodents this cycle, called the estrous cycle, lasts approximately 4-5 days. The success of reproduction in all mammals depends on the function of the hypothalamus-pituitary-gonads axis. In females, gonadotropin-releasing hormone (GnRH) neurons present in the septal area and hypothalamus send their axons to median eminence. GnRH released there reaches the anterior pituitary where the gonadotrophs are stimulated to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In the peripheral circulation, these hormones stimulate specific cells in the ovary leading to ovulation. Ovarian follicles secrete estrogen (E2) that reaches the hypothalamus. Most of the time, the plasma concentration of E2 is low. However, during the pre-ovulatory period E2 secretion reaches a peak, and GnRH neurons are stimulated (Sarkar et al., 1976;Freeman, 1994). E2 seems to regulate GnRH neurons indirectly, via interneurons. However, there are many questions needing to be answered in this field. Importantly, because E2 has a myriad of effects, questions are raised not only in the neuroendocrine field, but also in the neurosciences (e.g. synaptic plasticity, memory and learning and neurodegenerative diseases) as well as fields studying cardiological and/or renal function, sodium and water equilibrium, etc.A short cycle length makes rodents an ideal animal model for investigating changes occurring during the reproductive cycle and historically rats have been the chosen model. Rats display, most of time, regular cycles; they are easy to manipulate; and the cycle is not disrupted easily even with the routine stress in the animal facility. However, as use of mice lines continues to increase, an understanding of the mouse estrous cycle is critical for investigators and in fact many knockout mice can exhibit puberty/fertility changes that can effect, simply, maintaining a knockout line. There are few published studies involving estrous cycle in mice. The stages of the estrous cycle are not as visually discernible as in rats, and handling mice requires more caution due to their aggressive behavior. M...

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Bridging the Gap Between People and Animals: The Roots of Social Behavior and Its Relationship to Pain

Acland

Lidhar

Martin

2018

Social and Interpersonal Dynamics in Pain

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Oxytocin secretion induced by osmotic stimulation in rats during the estrous cycle and after ovariectomy and hormone replacement therapy

Cited by 23 publications

References 48 publications

Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity

Assessing Reproductive Status/Stages in Mice

Bridging the Gap Between People and Animals: The Roots of Social Behavior and Its Relationship to Pain

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