Modulation of the activity of vasopressinergic neurons by estrogen in rats refed with normal or sodium-free food after fasting

Lucio-Oliveira, F.; Traslaviña, Guillermo A. Ariza; Franci, Celso Rodrigues

doi:10.1016/j.neuroscience.2014.09.076

Cited by 3 publications

(9 citation statements)

References 52 publications

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“…An increase in c-Fos-immunoreactivity in SON vasopressin neurones in response to re-feeding after food restriction was previously noted (11). However, this is likely due to an osmotic stimulus (42). We have shown that plasma osmolarity and plasma sodium concentrations do not change with SCM gavage.…”

Section: Discussionsupporting

confidence: 59%

High-Sugar, but Not High-Fat, Food Activates Supraoptic Nucleus Neurons in the Male Rat

2017

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Oxytocin is a potent anorexigen and is believed to have a role in satiety signaling. We developed rat models to study the activity of oxytocin neurons in response to voluntary consumption or oral gavage of foods using c-Fos immunohistochemistry and in vivo electrophysiology. Using c-Fos expression as an indirect marker of neural activation, we showed that the percentage of magnocellular oxytocin neurons expressing c-Fos increased with voluntary consumption of sweetened condensed milk (SCM). To model the effect of food in the stomach, we gavaged anesthetized rats with SCM. The percentage of supraoptic nucleus and paraventricular nucleus magnocellular oxytocin-immunoreactive neurons expressing c-Fos increased with SCM gavage but not with gastric distention. To further examine the activity of the supraoptic nucleus, we made in vivo electrophysiological recordings from SON neurons, where anesthetized rats were gavaged with SCM or single cream. Pharmacologically identified oxytocin neurons responded to SCM gavage with a linear, proportional, and sustained increase in firing rate, but cream gavage resulted in a transient reduction in firing rate. Blood glucose increased after SCM gavage but not cream gavage. Plasma osmolarity and plasma sodium were unchanged throughout. We show that in response to high-sugar, but not high-fat, food in the stomach, there is an increase in the activity of oxytocin neurons. This does not appear to be a consequence of stomach distention or changes in osmotic pressure. Our data suggest that the presence of specific foods with different macronutrient profiles in the stomach differentially regulates the activity of oxytocin neurons.

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Section: Discussionsupporting

confidence: 59%

High-Sugar, but Not High-Fat, Food Activates Supraoptic Nucleus Neurons in the Male Rat

2017

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“…The animals were kept since their birth under conditions of stable temperature and humidity, 12 h light/dark cycles and food and water provided ad libitum (Animal Facility of the Institute of Physiology, Czech Academy of Sciences). We employed a previously reported protocol to challenge the peptide producing system of the SON, refeeding with standard chow for 2 h after 2 days of fasting (Figure 1A), which increases the activity of AVP neurons (Lucio-Oliveira et al, 2015). Experiments were performed in 30- to 32-day-old Wistar rats.…”

Section: Methodsmentioning

confidence: 99%

“…Two experimental conditions that have been widely used to stimulate the synthesis and release of these peptides are lactation for OT (de Kock et al, 2004; Panatier and Oliet, 2006) and water deprivation or refeeding after fasting for AVP (Carreno et al, 2011; Gottlieb et al, 2011; Yao et al, 2012; Yoshimura et al, 2013; Lucio-Oliveira et al, 2015). Refeeding after fasting represents a complex stimulation to hormone secretion involving the volume/baroreceptors and peripheral/central osmoreceptors (Burlet et al, 1992) that may involve neurotransmitter signaling at different levels.…”

Section: Introductionmentioning

confidence: 99%

“…In the present study, we tested a hypothesis that P2XRs might play a role in the release of AVP from SON neurons stimulated through fasting/refeeding. We examined the effect of 2 h of food intake after 48 h of starvation (Lucio-Oliveira et al, 2015) on AVP, OT, P2XR and P2YR mRNA expression and ATP-induced electrophysiological responses in the SON neurons in rat brain slices. Normally fed rats of the same age and sex were used as controls for this condition.…”

Section: Introductionmentioning

confidence: 99%

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P2X2 Receptor Expression and Function Is Upregulated in the Rat Supraoptic Nucleus Stimulated Through Refeeding After Fasting

Ivetic

Bhattacharyya

Zemková

2019

Front. Cell. Neurosci.

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Magnocellular neurons in the supraoptic nucleus (SON), which synthesize and release arginine vasopressin (AVP) and oxytocin (OT), express several subtypes of ATP-stimulated purinergic P2X receptors (P2XR) that modulate neuronal activity as well as neurotransmitter and hormone release. However, the physiological impact of this modulation is not well understood. Here, we tested a hypothesis that P2XRs play a role in the sustained release of hormones from SON neurons stimulated through fasting/refeeding. We studied the effect of 2 h of refeeding after 48 h of fasting on P2XR and P2YR mRNA expression and ATP-induced presynaptic and postsynaptic responses in the SON of 30-day-old rats. Quantitative real-time PCR revealed that the expression of P2X2R and AVP mRNA was upregulated, whereas P2X4R, P2X7R, P2Y2R, and OT mRNA levels were not significantly changed and P2Y1R mRNA expression was decreased. Whole-cell patch clamp recordings performed on isolated rat brain slices showed that the amplitude of the ATP-stimulated somatic current and the ATP-induced increases in the frequency of spontaneous GABAergic inhibitory postsynaptic currents were significantly higher in SON neurons from fasted/refed rats than in SON neurons from normally fed rats. No evidence was found for changes in the presynaptic effect of ATP in SON neurons not expressing somatic P2XRs. These results suggest that the increased activity of SON neurons synthesizing AVP is associated with enhanced expression of P2X2Rs on neuronal cell bodies and their GABAergic presynaptic nerve terminals.

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“…After surgery, all rats were treated with a prophylactic dose of pentabiotic (0.1 ml/rat, Fort Dodge, Campinas, Brazil) and analgesic flunixin meglumine (2.5 mg/kg i.m., Banamine V R , Schering-Plough, Rio de Janeiro, Brazil). 16 Fourteen days after surgery, the animals were distributed in six groups as follows and treated orally for 21 days: group 1: 0.1 ml propylene glycol þ 0.1 ml hydroalcoholic solution; group 2: 50 mg/kg estradiol benzoate; group 3: 0.75 mg/kg raloxifene; group 4: 80 mg/kg C. esculenta FG; group 5: 50 mg/kg estradiol þ 0.75 mg/kg raloxifene, and group 6: 0.75 mg/kg raloxifene þ 80 mg/kg C. esculenta FG.…”

Section: Experiments With Extract Fractions From Three Plant Species Amentioning

confidence: 99%

Effects of estrogen-like plant compounds on the vaginal epithelium pituitary, adrenal glands, and uterus of rats

Rodrigues

Moreira

Rossete

et al. 2018

Exp Biol Med (Maywood)

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Plant species with recognized estrogenic activity and widely used by Brazil’s female population to prevent the unpleasant symptoms of menopause were investigated in this work to demonstrate if constituents of taro-inhame ( Colocasia esculenta), cumaru ( Dipteryx odorata), and camapu ( Physalis angulata) have the ability to mimic or interfere with the action of estrogens. Moreover, their potential use as natural sources of estrogen-like substances for hormone replacement therapy was evaluated. (a) In vivo pharmacological assays were conducted to determine the estrogenic effects of D. odorata isoflavone-rich extract, P. angulata physalin-rich extract, and C. esculenta flavonoid glycoside-rich fraction (FG) on endocrine glands and reproductive organs of female rats at three different stages of the life cycle. The protocols consisted of uterotrophic assays and cytological evaluation of vaginal smears to detect mucosa cell alterations correlated with changes in hormone levels in each phase of the estrous cycle of female rats. The results indicated that C. esculenta FG exhibited estrogenic activity in prepubescent, pubescent, and adult ovariectomized female rats, while D. odorata isoflavones only promoted a weight increase in the pituitary gland of prepubescent rats after prolonged treatment and P. angulata physalins induced a weight increment in the adrenal glands of ovariectomized rats. Additionally, C. esculenta exerted a significant effect on the opening of the vaginal canal in prepubescent rats and on vaginal epithelium. Prolonged treatment of ovariectomized rats with FG altered the proportion of different types of vaginal epithelial cells in these animals, suggesting an interference of FG with estrogen levels. Colocasia esculenta FG induced hypertrophy of the uterus and pituitary in ovariectomized rats similar to estradiol. To elucidate the mechanism of action of FG, its effects were compared to those of estradiol and of the selective estrogen receptor modulator raloxifene. The results suggest that the efficacy of C. esculenta FG is mediated by binding to selective estrogen receptors present in each organ and that raloxifene inhibits the mechanism of action of FG in the same way as it inhibits the effects of estradiol. The overall findings indicate that C. esculenta FG mimics the action of estrogens, with reduced harmful effects on specific tissues. Impact statement The results of this work provide preliminary evidence that ovariectomized rats display the vaginal smear cells typical of the estrous phase of mature rats after long-term ingestion of Colocasia esculenta flavonoid glycosides. Moreover, the treatment caused beneficial effects on endocrine and reproductive organs compared to estradiol. The animals did not exhibit significant body weight alterations among the groups, demonstrating the maintenance of standard metabolism and energy balance. The overall findings obtained with the rat model of menopause highlight the importance of dietary consumption of C. esculenta constituents as potential selective estrogen receptor modulators and suggest that they may prevent some of the metabolic disorders related to estrogen deficiency.

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Modulation of the activity of vasopressinergic neurons by estrogen in rats refed with normal or sodium-free food after fasting

Cited by 3 publications

References 52 publications

High-Sugar, but Not High-Fat, Food Activates Supraoptic Nucleus Neurons in the Male Rat

High-Sugar, but Not High-Fat, Food Activates Supraoptic Nucleus Neurons in the Male Rat

P2X2 Receptor Expression and Function Is Upregulated in the Rat Supraoptic Nucleus Stimulated Through Refeeding After Fasting

Effects of estrogen-like plant compounds on the vaginal epithelium pituitary, adrenal glands, and uterus of rats

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