Central release of oxytocin and the ventromedial hypothalamus

Sabatier, Nancy; Rowe, Iain; Leng, Gareth

doi:10.1042/bst0351247

Cited by 38 publications

(36 citation statements)

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“…The VMH contains oxytocin binding sites (40) and targeted administration of oxytocin to the VMH results in increased energy expenditure and reduced feeding (1). We observed a nonsignificant increase in c-Fos expression in the VMH after SCM gavage but it is not clear whether this represents a direct downstream effect of central oxytocin release after SCM gavage or is related more broadly to satiety signalling (41).…”

Section: Discussionmentioning

confidence: 95%

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: Discussionmentioning

confidence: 95%

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

2017

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“…These genes play crucial roles in regulating the production and release of OT and AVP in the PVN. Specifically, agonism of melanocortin 4 receptor (Mc4R) in magnocellular neurons induces dendritic secretion of OT (80), an effect which is anxiolytic (81,82). In female rats, neonatal BPA exposure (50-mg/kg bw or 50-g/kg bw by sc injection) significantly increased OT-ir neuron numbers in the anterior PVN of female rats (19), a result interpreted as potentially indicative of OT sequestration.…”

Section: Discussionmentioning

confidence: 97%

A Novel Model for Neuroendocrine Toxicology: Neurobehavioral Effects of BPA Exposure in a Prosocial Species, the Prairie Vole (Microtus ochrogaster)

et al. 2014

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Impacts on brain and behavior have been reported in laboratory rodents after developmental exposure to bisphenol A (BPA), raising concerns about possible human effects. Epidemiological data suggest links between prenatal BPA exposure and altered affective behaviors in children, but potential mechanisms are unclear. Disruption of mesolimbic oxytocin (OT)/vasopressin (AVP) pathways have been proposed, but supporting evidence is minimal. To address these data gaps, we employed a novel animal model for neuroendocrine toxicology: the prairie vole (Microtus ochrogaster), which are more prosocial than lab rats or mice. Male and female prairie vole pups were orally exposed to 5-μg/kg body weight (bw)/d, 50-μg/kg bw/d, or 50-mg/kg bw/d BPA or vehicle over postnatal days 8-14. Subjects were tested as juveniles in open field and novel social tests and for partner preference as adults. Brains were then collected and assessed for immunoreactive (ir) tyrosine hydroxylase (TH) (a dopamine marker) neurons in the principal bed nucleus of the stria terminalis (pBNST) and TH-ir, OT-ir, and AVP-ir neurons in the paraventricular nucleus of the hypothalamus (PVN). Female open field activity indicated hyperactivity at the lowest dose and anxiety at the highest dose. Effects on social interactions were also observed, and partner preference formation was mildly inhibited at all dose levels. BPA masculinized principal bed nucleus of the stria terminalis TH-ir neuron numbers in females. Additionally, 50-mg/kg bw BPA-exposed females had more AVP-ir neurons in the anterior PVN and fewer OT-ir neurons in the posterior PVN. At the 2 lowest doses, BPA eliminated sex differences in PVN TH-ir neuron numbers and reversed this sex difference at the highest dose. Minimal behavioral effects were observed in BPA-exposed males. These data support the hypothesis that BPA alters affective behaviors, potentially via disruption of OT/AVP pathways.

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“…Their work shows that dendritic release from magnocellular PVN and SON neurons can influence behavior (Ludwig and Leng, 2006). They suggest, for example, that the lordotic response (see below), shown to rely on VMH Oxtr, may reflect action of Oxt that diffused to the VMH from the PVN and SON after dendritic release (Sabatier et al , 2007). …”

Section: Introductionmentioning

confidence: 99%

Oxytocin: The Great Facilitator of Life

Lee

Macbeth

Pagani

et al. 2009

Progress in Neurobiology

646

634

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Oxytocin (Oxt) is a nonapeptide hormone best known for its role in lactation and parturition. Since 1906 when its uterine-contracting properties were described until 50 years later when its sequence was elucidated, research focused on its peripheral roles in reproduction. Only over the past several decades have researchers focused on what functions Oxt might have in the brain, the subject of this review. Immunohistochemical studies revealed that magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei are the neurons of origin for the Oxt released from the posterior pituitary. Smaller cells in various parts of the brain, as well as release from magnocellular dendrites, provide the Oxt responsible for modulating various behaviors at its only identified receptor. Although Oxt is implicated in a variety of “non-social” behaviors, such as learning, anxiety, feeding and pain perception, it is Oxt’s roles in various social behaviors that have come to the fore recently. Oxt is important for social memory and attachment, sexual and maternal behavior, and aggression. Recent work implicates Oxt in human bonding and trust as well. Human disorders characterized by aberrant social interactions, such as autism and schizophrenia, may also involve Oxt expression. Many, if not most, of Oxt’s functions, from social interactions (affiliation, aggression) and sexual behavior to eventual parturition, lactation and maternal behavior, may be viewed as specifically facilitating

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Central release of oxytocin and the ventromedial hypothalamus

Cited by 38 publications

References 50 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

A Novel Model for Neuroendocrine Toxicology: Neurobehavioral Effects of BPA Exposure in a Prosocial Species, the Prairie Vole (Microtus ochrogaster)

Oxytocin: The Great Facilitator of Life

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