Electrophysiological Effects of Kainic Acid on Vasopressin‐<scp>Enhanced Green Fluorescent Protein</scp> and Oxytocin‐<scp>Monomeric Red Fluorescent Protein </scp>1 Neurones Isolated from the Supraoptic Nucleus in Transgenic Rats

Ohkubo, Jun‐ichi; Ohbuchi, Toyoaki; Yoshimura, Mitsuhiro; Maruyama, Takashi; Ishikura, Toru; Matsuura, Takanori; Suzuki, Hitoshi; Ueta, Yoichi

doi:10.1111/jne.12128

Cited by 9 publications

(4 citation statements)

References 29 publications

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“…Our present studies in acute slices and organotypic cultures constitute an initial effort to decrypt some structure-function relationships in the magnocellular neuroendocrine circuits, complementing current efforts to decipher the electrical behavior of hypothalamic neuroendocrine cells (Osterstock et al, 2010 ; Murphy et al, 2012 ; MacGregor and Leng, 2013 ; Wamsteeker Cusulin et al, 2013 ; Ohkubo et al, 2014 ; Briffaud et al, 2015 ; Iremonger and Herbison, 2015 ; Royo et al, 2015 ). Although, this ideally at some point requires analysis and manipulations of the neuroendocrine networks in vivo (Campos and Herbison, 2014 ), a wealth of ex vivo studies should also continue to provide irreplaceable information.…”

Section: Discussionmentioning

confidence: 73%

Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices

2016

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Hypothalamic neurohormones are released in a pulsatile manner. The mechanisms of this pulsatility remain poorly understood and several hypotheses are available, depending upon the neuroendocrine system considered. Among these systems, hypothalamo-neurohypophyseal magnocellular neurons have been early-considered models, as they typically display an electrical activity consisting of bursts of action potentials that is optimal for the release of boluses of the neurohormones oxytocin and vasopressin. The cellular mechanisms underlying this bursting behavior have been studied in vitro, using either acute slices of the adult hypothalamus, or organotypic cultures of neonatal hypothalamic tissue. We have recently proposed, from experiments in organotypic cultures, that specific central pattern generator networks, upstream of magnocellular neurons, determine their bursting activity. Here, we have tested whether a similar hypothesis can be derived from in vitro experiments in acute slices of the adult hypothalamus. To this aim we have screened our electrophysiological recordings of the magnocellular neurons, previously obtained from acute slices, with an analysis of autocorrelation of action potentials to detect a rhythmic drive as we recently did for organotypic cultures. This confirmed that the bursting behavior of magnocellular neurons is governed by central pattern generator networks whose rhythmic drive, and thus probably integrity, is however less satisfactorily preserved in the acute slices from adult brains.

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Section: Discussionmentioning

confidence: 73%

Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices

2016

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“…OXT is mainly produced in neurosecretory neurons located in the SON and PVN in the hypothalamus. We successfully generated transgenic rats bearing an OXT-mRFP1 fusion gene, which resulted in the visualization of OXT expression 19,20,[25][26][27][28] . The PVN is divided into regions such as apPVN, dpPVN, and mPVN, and previous studies with the OXT-mRFP1 transgenic rats reported different effects 29 .…”

Section: Discussionmentioning

confidence: 99%

Oestrogen-Dependent Oxytocin Dynamics in the Hypothalamus of Female Rats

Nishimura¹,

Yoshino²,

Ikeda³

et al. 2021

Preprint

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Oxytocin (OXT) is produced in the hypothalamic nuclei and is secreted into systemic circulation from the posterior pituitary gland (PP). In the central nervous system, OXT regulates behaviours including maternal and feeding behaviours. Our aim was to evaluate whether oestrogen regulates hypothalamic OXT dynamics. Herein, we provide the first evidence that OXT dynamics in the hypothalamus vary with sex and that oestrogen may modulate dynamic changes in OXT levels, using OXT-mRFP1 transgenic rats. The fluorescence intensity of OXT-mRFP1 in the hypothalamic nuclei and PP was most strongly expressed during the oestrus stage in female rats and decreased significantly in ovariectomised rats. Oestrogen replacement caused significant increases in the fluorescent intensities in the hypothalamic nuclei and PP in a dose-dependent manner. This was also demonstrated in feeding behaviour and hypothalamic Fos neurons using immunohistochemistry. Hypothalamic OXT expression was oestrogen dependent and could be enhanced centrally by the administration of oestrogen.

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“…1B). AVP-eGFP Tg rats provide a unique model for visualizing the molecular dynamics of AVP in vivo and for live imaging and/or electrophysiology of identified AVP neurons without any specific histological labeling [13][14][15][16][17][18][19][20]. Previous studies have demonstrated that the exposure of AVP-eGFP Tg rats to dehydration induced significantly greater expression of GFP in PVN and SON neurons, mirroring that of native AVP [8,9].…”

Section: Introductionmentioning

confidence: 99%

In vivo processing and release into the circulation of GFP fusion protein in arginine vasopressin enhanced GFP transgenic rats: response to osmotic stimulation

et al. 2015

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Arginine vasopressin (AVP) is a neurohypophysial hormone synthesized as a part of a prepropeptide precursor containing the signal peptide, AVP hormone, AVP-associated neurophysin II and copeptin in the hypothalamic neurosecretory neurons. A transgenic (Tg) rat line expressing the AVP-eGFP fusion gene has been generated. To establish the AVP-eGFP Tg rat as a unique model for an analysis of AVP dynamics in vivo, we first examined the in vivo molecular dynamics of the AVP-eGFP fusion gene, and then the release of GFP in response to physiological stimuli. Double immunoelectron microscopy demonstrated that GFP was specifically localized in neurosecretory vesicles of AVP neurons in this Tg rat. After stimulation of the posterior pituitary with high potassium we demonstrated the exocytosis of AVP neurosecretory vesicles containing GFP at the ultrastructural level. Biochemical analyses indicated that the AVP-eGFP fusion gene is subjected to in vivo post-translational modifications like the native AVP gene, and is packaged into neurosecretory vesicles as a fusion protein: copeptin 1-14 -GFP. Moreover, GFP release into the circulating blood appeared to be augmented after osmotic stimulation, like native AVP. Thus, here we show for the first time the in vivo molecular processing of the AVP-eGFP fusion gene and stimulated secretion after osmotic stimulation in rats. Because GFP behaved like native AVP in the hypothalamopituitary axis, and in particular was released into the circulation in response to a physiological stimulus, the AVP-eGFP Tg rat model appears to be a powerful tool for analyzing neuroendocrine systems at the organismal level.

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Electrophysiological Effects of Kainic Acid on Vasopressin‐Enhanced Green Fluorescent Protein and Oxytocin‐Monomeric Red Fluorescent Protein 1 Neurones Isolated from the Supraoptic Nucleus in Transgenic Rats

Cited by 9 publications

References 29 publications

Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices

Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices

Oestrogen-Dependent Oxytocin Dynamics in the Hypothalamus of Female Rats

In vivo processing and release into the circulation of GFP fusion protein in arginine vasopressin enhanced GFP transgenic rats: response to osmotic stimulation

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