Dendrites of hypothalamic magnocellular neurons release neurohypophysial peptides by exocytosis

Pow, David V.; Morris, John F.

doi:10.1016/0306-4522(89)90091-2

Cited by 435 publications

(301 citation statements)

References 26 publications

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“…It has been described that-in addition to the synthesis in the paraventricular and supraoptic nuclei of the hypothalamus-lesser amounts of oxytocin are generated in the bed nucleus of the striaterminalis, medial preoptic area, and lateral amygdala, depending on the species [21]. The release of oxytocin in humans is known not to happen exclusively via axonal secretion in the posterior pituitary but also from the dendrites (opposed to the axons) for intracerebral release [22][23][24]. By discrete grading and comparisons of CP patients with grade 1 hypothalamic surgical damage (damage exclusively to the anterior hypothalamic structures) and grade 2 (damage of anterior and posterior hypothalamic regions), we found that patients with grade 1 damage only to the anterior hypothalamus had a lower oxytocin level before breakfast compared to patients with grade 2 damage and to patients without any hypothalamic damage.…”

Section: Discussionmentioning

confidence: 99%

Oxytocin in survivors of childhood-onset craniopharyngioma

et al. 2016

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Section: Discussionmentioning

confidence: 99%

Oxytocin in survivors of childhood-onset craniopharyngioma

et al. 2016

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“…This mismatch might be rectified by postulating a more complex mechanism for dynorphin release, such as delays arising from mobilization effects (Pow and Morris, 1989;Kits and Mansvelder, 2000). However, a simpler way to prolong the active phase, without changing the length of the silent phase, is instead to allow ⌬ to depend on previous activity.…”

Section: Action Of Dynorphinmentioning

confidence: 99%

Burst Initiation and Termination in Phasic Vasopressin Cells of the Rat Supraoptic Nucleus: A Combined Mathematical, Electrical, and Calcium Fluorescence Study

Roper¹,

Callaway²,

Armstrong³

2004

J. Neurosci.

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Vasopressin secreting neurons of the rat hypothalamus discharge lengthy, repeating bursts of action potentials in response to physiological stress. Although many electrical currents and calcium-dependent processes have been isolated and analyzed in these cells, their interactions are less well fathomed. In particular, the mechanism of how each burst is triggered, sustained, and terminated is poorly understood. We present a mathematical model for the bursting mechanism, and we support our model with new simultaneous electrical recording and calcium imaging data. We show that bursts can be initiated by spike-dependent calcium influx, and we propose that the resulting elevation of bulk calcium inhibits a persistent potassium current. This inhibition depolarizes the cell above threshold and so triggers regenerative spiking and further calcium influx. We present imaging data to show that bulk calcium reaches a plateau within the first few seconds of the burst, and our model indicates that this plateau occurs when calcium influx is balanced by efflux and uptake into stores. We conjecture that the burst is terminated by a slow, progressive desensitization to calcium of the potassium leak current. Finally, we propose that the opioid dynorphin, which is known to be secreted from the somatodendritic region and has been shown previously to regulate burst length and phasic activity in these cells, is the autocrine messenger for this desensitization.

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“…However, the significance of the sexual difference in the AVP or CP systems remains unknown. Since only a fragment (possibly CP [1][2][3][4][5][6][7][8][9][10][11][12][13][14] of CP is expressed in these Tg rats as part of the fusion protein with GFP, it is not clear if CP would be functional in these Tg rats in vivo. In fact, some of the exaggerated responses of this Tg animal might be related to this mutation [13].…”

Section: Discussionmentioning

confidence: 99%

“…AVP preproprotein (A) and AVP-GFP fusion preproprotein (B) consist of the signal peptide (SP), AVP hormone, AVP-associated neurophysin (NP) II and the glycoprotein copeptin (CP), where the glycan is represented by a diamond. The translation as a CP [1][2][3][4][5][6][7][8][9][10][11][12][13][14] is expected in this transgene, and the sixth asparagine of CP is expected to be a glycosylation site. The numbers denote the amino acids present in each region.…”

Section: In Vivo Subcellular Localization Of Gfp In Avp Neurons By Immentioning

confidence: 99%

“…After GFP-IP, the CP 7-14 positive band was only detected at the same level of 28 kDa (B). The second incubation with GFP antibodies demonstrated that the CP 7-14 positive proteins appeared to exist as CP [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and GFP fusion proteins (B). Western analyses were repeated independently three times by using different samples and gave similar results.…”

Section: In Vivo Subcellular Localization Of Gfp In Avp Neurons By Immentioning

confidence: 99%

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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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Dendrites of hypothalamic magnocellular neurons release neurohypophysial peptides by exocytosis

Cited by 435 publications

References 26 publications

Oxytocin in survivors of childhood-onset craniopharyngioma

Oxytocin in survivors of childhood-onset craniopharyngioma

Burst Initiation and Termination in Phasic Vasopressin Cells of the Rat Supraoptic Nucleus: A Combined Mathematical, Electrical, and Calcium Fluorescence Study

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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