Central Nervous System Control of Oxytocin Secretion during Lactation

Armstrong, William E.

doi:10.1016/b978-0-12-397175-3.00013-2

Cited by 12 publications

(24 citation statements)

References 343 publications

(387 reference statements)

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“…In steroid replacement experiments in ovariectomised rats, the withdrawal of progesterone in the presence of oestrogen produces an increase in maternal behaviour , an up‐regulation of OTR binding and increased OT mRNA . Similarly, in intact animals, this late gestational period and lactation are also associated with an up‐regulation of OT mRNA, OTR mRNA, OTR binding, and significant morphological and synaptic plasticity in magnocellular neurones . These events are also accompanied by increased somatodendritic OT release .…”

Section: Discussionmentioning

confidence: 99%

“…One of the key neurohypophysial hormones, oxytocin (OT), is synthesised and released from the magnocellular cells (MNCs) of the supraoptic nucleus (SON) and paraventricular nucleus (PVN). Although best known to activate peripheral OT receptors (OTRs) mediating the induction of labour through uterine contractions, and the mammary myoepithelial cell contractions necessary for milk ejection during lactation , OT also acts as a peptidergic neurotransmitter in the brain , which contains an abundance of OTRs . In the SON and PVN, OT is released from the dendrites and somata to act on OTRs on OT neurones themselves.…”

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confidence: 99%

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Late Pregnancy is a Critical Period for Changes in Phosphorylated Mitogen‐Activated Protein Kinase/Extracellular Signal‐Regulated Kinase 1/2 in Oxytocin Neurones

Chandaka

Wang

Senogles

et al. 2016

J Neuroendocrinology

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This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.The physiological demands of parturition and lactation lead to the increased pulsatile release of oxytocin (OT) into the circulation from the neurohypophysial axons of OT neurones in the supraoptic (SON) and paraventricular (PVN) nuclei. These states of increased OT release are accompanied by a significant plasticity in magnocellular OT neurones and their synaptic connections, and many of these changes require activation of a central OT receptor. The mitogen-activated protein kinase/extracellular signal-regulated kinase pathway (MAPK/ERK) is assumed to be up-regulated in the PVN during lactation, and many of the effects of OT in peripheral and brain tissue are mediated through a MAPK/ERK pathway. The present study investigated whether this pathway is altered in the SON and PVN during late pregnancy [embryonic day (E)20-21], which is a critical period for OT plasticity induction, and for lactation, when plastic changes are sustained. Based on immunoreactivity for phosphorylated ERK1/2 (pERK1/2), the results suggest an enhanced activation of MAPK/ERK pathway in OT neurones specifically during late pregnancy in both the SON and PVN. Although immunoblots from the SON confirm this pregnancy-associated up-regulation in late pregnancy, they also suggest enhancement into lactation as well. Together, the results suggest an important role for the MAPK/ERK pathway during reproductive changes in the SON and PVN.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Late Pregnancy is a Critical Period for Changes in Phosphorylated Mitogen‐Activated Protein Kinase/Extracellular Signal‐Regulated Kinase 1/2 in Oxytocin Neurones

Chandaka

Wang

Senogles

et al. 2016

J Neuroendocrinology

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“…After 24 hours of dehydration, L‐channel Ca 2+ density accounts for an increase in Ca 2+ current density in both OT and VP neurones . Water deprivation or salt loading not only activates both OT and VP neurones, but also leads to many morphological, electrophysiological and synaptic changes in magnocellular neurones and associated glia similar to those observed specifically in OT neurones during lactation …”

Section: Properties Of Identified Ot and Vp Neuronesmentioning

confidence: 87%

Electrophysiological properties of identified oxytocin and vasopressin neurones

Armstrong

Foehring

Kirchner

et al. 2019

J Neuroendocrinology

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To understand the contribution of intrinsic membrane properties to the different in vivo firing patterns of oxytocin (OT) and vasopressin (VP) neurones, in vitro studies are needed, where stable intracellular recordings can be made. Combining immunochemistry for OT and VP and intracellular dye injections allows characterisation of identified OT and VP neurones, and several differences between the two cell types have emerged. These include a greater transient K+ current that delays spiking to stimulus onset, and a higher Na+ current density leading to greater spike amplitude and a more stable spike threshold, in VP neurones. VP neurones also show a greater incidence of both fast and slow Ca2+‐dependent depolarising afterpotentials, the latter of which summate to plateau potentials and contribute to phasic bursting. By contrast, OT neurones exhibit a sustained outwardly rectifying potential (SOR), as well as a consequent depolarising rebound potential, not found in VP neurones. The SOR makes OT neurones more susceptible to spontaneous inhibitory synaptic inputs and correlates with a longer period of spike frequency adaptation in these neurones. Although both types exhibit prominent Ca2+‐dependent afterhyperpolarising potentials (AHPs) that limit firing rate and contribute to bursting patterns, Ca2+‐dependent AHPs in OT neurones selectively show significant increases during pregnancy and lactation. In OT neurones, but not VP neurones, AHPs are highly dependent on the constitutive presence of the second messenger, phosphatidylinositol 4,5‐bisphosphate, which permissively gates N‐type channels that contribute the Ca2+ during spike trains that activates the AHP. By contrast to the intrinsic properties supporting phasic bursting in VP neurones, the synchronous bursting of OT neurones has only been demonstrated in vitro in cultured hypothalamic explants and is completely dependent on synaptic transmission. Additional differences in Ca2+ channel expression between the two neurosecretory terminal types suggests these channels are also critical players in the differential release of OT and VP during repetitive spiking, in addition to their importance to the potentials controlling firing patterns.

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“…In contrast, in the multiplex model of homeorhesis provided by lactation, hormones including prolactin, growth hormone, glucocorticoids, insulin-like growth factor-1, and thyroid hormones produced both centrally and in peripheral tissues create an endocrine environment that modifies the expression of genes and the functions of pathways that provide the homeostatic settings for metabolic activities throughout the animal. Thus, visual and tactile stimuli from the external environment are integrated with neural and somatic signals from the internal environment in maintenance of the physiological state of lactation (Akers et al, 2000;Bauman, 2000;Armstrong, 2015). Within this multiplex hormonal environment, lactation performance is influenced by numerous genes influencing hormonal regulation, metabolism, and mammary gland function.…”

Section: Homeorhetic Regulation Of Temperament Traitsmentioning

confidence: 99%

Adrenergic Tone as an Intermediary in the Temperament Syndrome Associated With Flight Speed in Beef Cattle

Colditz

2021

Front. Anim. Sci.

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The temperament of farm animals can influence their resilience to everyday variations within the managed production environment and has been under strong direct and indirect selection during the course of domestication. A prominent objective measure used for assessing temperament in beef cattle is the behavioral flight response to release from confinement in a crush or chute. This behavioral measure, termed flight speed (also known as escape velocity) is associated with physiological processes including body temperature, feeding behavior, growth rate, carcass composition, immune function, and health outcomes. This review examines the functional links between this suite of traits and adrenergic activity of the sympathetic nervous system and the adrenomedullary hormonal system. It is suggested that flight speed is the behavioral aspect of an underlying “flightiness” temperament syndrome, and that elevated adrenergic tone in animals with a high level of flightiness (i.e., flighty animals) tunes physiological activities toward a sustained “fight or flight” defense profile that reduces productivity and the capacity to flourish within the production environment. Nonetheless, despite a common influence of adrenergic tone on this suite of traits, variation in each trait is also influenced by other regulatory pathways and by the capacity of tissues to respond to a range of modulators in addition to adrenergic stimuli. It is suggested that tuning by adrenergic tone is an example of homeorhetic regulation that can help account for the persistent expression of behavioral and somatic traits associated with the flight speed temperament syndrome across the life of the animal. At a population level, temperament may modulate ecological fit within and across generations in the face of environmental variability and change. Associations of flight speed with the psychological affective state of the animal, and implications for welfare are also considered. The review will help advance understanding of the developmental biology and physiological regulation of temperament syndromes.

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Central Nervous System Control of Oxytocin Secretion during Lactation

Cited by 12 publications

References 343 publications

Late Pregnancy is a Critical Period for Changes in Phosphorylated Mitogen‐Activated Protein Kinase/Extracellular Signal‐Regulated Kinase 1/2 in Oxytocin Neurones

Late Pregnancy is a Critical Period for Changes in Phosphorylated Mitogen‐Activated Protein Kinase/Extracellular Signal‐Regulated Kinase 1/2 in Oxytocin Neurones

Electrophysiological properties of identified oxytocin and vasopressin neurones

Adrenergic Tone as an Intermediary in the Temperament Syndrome Associated With Flight Speed in Beef Cattle

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