Excitatory Synaptic Drive Offsets Opioid Inhibition of Oxytocin Neurons<sup>a</sup>

Pumford, K. M.; Leng, Gareth; Ja, Russell

doi:10.1111/j.1749-6632.1993.tb55620.x

Cited by 5 publications

(9 citation statements)

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“…Inhibitory response to labor-induced oxytocin release, both of k and m agonists, depends on the number and intensity of sensory afferences 38 , which confirms the possibility of oxytocin release inhibition by opioids being labor phase-dependent.…”

Section: Discussionsupporting

confidence: 55%

“…Na segunda fase do trabalho de parto, a morfina, por via venosa, não foi capaz de bloquear a liberação de ocitocina, provavelmente, devido à maior intensidade do estí-mulo e à baixa efetividade analgésica da morfina venosa em baixas doses nesta fase 37 . A resposta inibitória na liberação de ocitocina devido ao trabalho de parto, tanto dos agonistas k quanto dos agonistas m, depende do número e intensidade das aferências sensitivas 38 , o que fortalece a possibilidade da inibição da liberação de ocitocina por opióides depender do estágio do trabalho de parto. A possibilidade de dispersão cefálica do sufentanil já foi discutida anteriormente.…”

Section: Discussionunclassified

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Efeitos da analgesia do sufentanil por via subaracnóidea e bupivacaína a 0,25% por via peridural sobre as concentrações plasmáticas de ocitocina e cortisol em gestantes em trabalho de parto

Stocche¹,

Garcia²,

Klamt³

2001

Rev. Bras. Anestesiol.

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Section: Discussionsupporting

confidence: 55%

Section: Discussionunclassified

Efeitos da analgesia do sufentanil por via subaracnóidea e bupivacaína a 0,25% por via peridural sobre as concentrações plasmáticas de ocitocina e cortisol em gestantes em trabalho de parto

Stocche¹,

Garcia²,

Klamt³

2001

Rev. Bras. Anestesiol.

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“…pertussis toxin, whereas those of U50,488 are unaffected ( Fig. 2C; Pumford, Leng & Russell, 1993 a). Pertussis toxin irreversibly nrbosylates Gil.…”

Section: Opioids and Oxytocin Neuronesmentioning

confidence: 94%

“…Sensitivity to U50,488 under these conditions remains unaltered (data not show n). Data from Pumford et al (1993 a). Vaughan, Rivier & Vale, 1988).…”

Section: Central Endogenous Opioid Peptide Inputs To Oxytocin Neuronesmentioning

confidence: 99%

Opioid tolerance and dependence in the magnocellular oxytocin system: a physiological mechanism?

Ja¹,

Leng²,

Rj³

1995

Experimental Physiology

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At the neurosecretory terminals in the neural lobe, oxytocin secretion is restrained by co‐secreted endogenous opioids, which act via kappa‐receptors. The co‐secreted opioids include products of pro‐dynorphin (released by both vasopressin and oxytocin terminals) and proenkephalin (released by oxytocin terminals). In morphine‐tolerant rats this opioid mechanism is more effective, but in late pregnancy it is less effective. Opioids also act directly on oxytocin cell bodies, via separate mu‐ and kappa‐receptors, inhibiting excitation by all stimuli tested, and also exert presynaptic and more distal actions on afferent systems. During chronic morphine exposure, tolerance and dependence develop in oxytocin neurones; the former involves reduction in mu‐opioid receptor density, while the latter may involve compensatory upregulation of mechanisms regulating Ca2+ influx. In mid‐pregnancy, the effectiveness of opioid mechanisms in the neural lobe increases, assisting the accumulation of oxytocin stores in advance of parturition, but by the end of pregnancy the effectiveness of these mechanisms is reduced. At this time, a separate endogenous opioid system, acting via mu‐receptors, actively restrains the electrical activity of oxytocin neurones. Release of this endogenous opioid inhibition may contribute to the increase in activity during parturition analogous to that occurring during morphine withdrawal excitation. Central opioid mechanisms retain the ability to control oxytocin neurones during parturition, and can interrupt established parturition by inhibiting oxytocin neurone firing rate in disadvantageous environmental circumstances.

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“…In addition to OXT itself, endogenous opioids were also known to significantly contribute to the regulation of OXT neurones in the peripartum period, 34,53,54 and we hypothesised that opioids also inhibit local OXT release from dendrites and perikarya within the SON at the end of pregnancy to prevent OXT secretion into blood and premature labour. 53 Indeed, similar to the disinhibiting effect of naloxone on OXT release within the septum mentioned above, 36 the opioid antagonist also elevated basal OXT release within the SON.…”

Section: Con S Equen Ce S Of Centr Al Ox T Rele a S E During L Ac Tmentioning

confidence: 99%

Tracking oxytocin functions in the rodent brain during the last 30 years: From push‐pull perfusion to chemogenetic silencing

Neumann

Landgraf²

2019

J Neuroendocrinology

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A short overview is provided of the last 30 years of oxytocin (and vasopressin) research performed in our laboratories, starting with attempts to monitor the release of this nonapeptide in the rodent brain during physiological conditions such as suckling in the lactating animal. Using push‐pull perfusion and microdialysis approaches, release patterns in hypothalamic and limbic brain regions could be characterised to occur from intact neuronal structures, to be independent of peripheral secretion into blood, and to respond differentially to various stimuli, particularly those related to reproduction and stress. Parallel efforts focused on the functional impact of central oxytocin release, including neuroendocrine and behavioural effects mediated by nonapeptide receptor interactions and subsequent intraneuronal signalling cascades. The use of a variety of sophisticated behavioural paradigms to manipulate central oxytocin release, along with pharmacological, genetic and pharmacogenetic approaches, revealed multiple consequences on social behaviours, particularly social fear.

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Excitatory Synaptic Drive Offsets Opioid Inhibition of Oxytocin Neurons^a

Cited by 5 publications

References 4 publications

Efeitos da analgesia do sufentanil por via subaracnóidea e bupivacaína a 0,25% por via peridural sobre as concentrações plasmáticas de ocitocina e cortisol em gestantes em trabalho de parto

Efeitos da analgesia do sufentanil por via subaracnóidea e bupivacaína a 0,25% por via peridural sobre as concentrações plasmáticas de ocitocina e cortisol em gestantes em trabalho de parto

Opioid tolerance and dependence in the magnocellular oxytocin system: a physiological mechanism?

Tracking oxytocin functions in the rodent brain during the last 30 years: From push‐pull perfusion to chemogenetic silencing

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Excitatory Synaptic Drive Offsets Opioid Inhibition of Oxytocin Neuronsa

Cited by 5 publications

References 4 publications

Efeitos da analgesia do sufentanil por via subaracnóidea e bupivacaína a 0,25% por via peridural sobre as concentrações plasmáticas de ocitocina e cortisol em gestantes em trabalho de parto

Efeitos da analgesia do sufentanil por via subaracnóidea e bupivacaína a 0,25% por via peridural sobre as concentrações plasmáticas de ocitocina e cortisol em gestantes em trabalho de parto

Opioid tolerance and dependence in the magnocellular oxytocin system: a physiological mechanism?

Tracking oxytocin functions in the rodent brain during the last 30 years: From push‐pull perfusion to chemogenetic silencing

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Excitatory Synaptic Drive Offsets Opioid Inhibition of Oxytocin Neurons^a