scholarly journals Variation of pro‐vasopressin processing in parvocellular and magnocellular neurons in the paraventricular nucleus of the hypothalamus: Evidence from the vasopressin‐related glycopeptide copeptin

2020 ◽  
Author(s):  
Natsuko Kawakami ◽  
Akito Otubo ◽  
Sho Maejima ◽  
Ashraf H. Talukder ◽  
Keita Satoh ◽  
...  
Keyword(s):  
Paraventricular Nucleus ◽  
Magnocellular Neurons

Vasopressin Increases GABAergic Inhibition of Rat Hypothalamic Paraventricular Nucleus Neurons In Vitro

2000 ◽  
Vol 83 (2) ◽  
pp. 705-711 ◽  
Author(s):  
M.L.H.J. Hermes ◽  
J. M. Ruijter ◽  
A. Klop ◽  
R. M. Buijs ◽  
L. P. Renaud
Keyword(s):  
Paraventricular Nucleus ◽  
Receptor Agonist ◽  
Hypothalamic Paraventricular Nucleus ◽  
Membrane Properties ◽  
Magnocellular Neurons ◽  
Membrane Hyperpolarization ◽  
Perforated Patch ◽  
Intrinsic Membrane Properties ◽  
Brain Slice Preparation

This investigation used an in vitro hypothalamic brain slice preparation and whole cell and perforated-patch recording to examine the response of magnocellular neurons in hypothalamic paraventricular nucleus (PVN) to bath applications of vasopressin (VP; 100–500 nM). In 22/38 cells, responses were characterized by an increase in the frequency of bicuculline-sensitive inhibitory postsynaptic potentials or currents with no detectable influence on excitatory postsynaptic events. Perforated-patch recordings confirmed that VP did not have an effect on intrinsic membrane properties of magnocellular PVN neurons ( n = 17). Analysis of intrinsic membrane properties obtained with perforated-patch recording ( n = 23) demonstrated that all of nine VP-sensitive neurons showed a rebound depolarization after transient membrane hyperpolarization from rest. By contrast, 12/14 nonresponding neurons displayed a delayed return to resting membrane potentials. Recordings of reversed inhibitory postsynaptic currents with chloride-loaded electrodes showed that responses to VP persisted in media containing glutamate receptor antagonists but were abolished in the presence of tetrodotoxin. In addition, responses were mimicked by vasotocin [Phe2, Orn8], a selective V1a receptor agonist, and blocked by [β-Mercapto-β,β-cyclopentamethylenepropionyl1,O-Me-Tyr2, Arg8]-VP (Manning compound), a V1a/OT receptor antagonist. Neither [deamino-Cys1,Val4,d-Arg8]-VP, a selective V2 receptor agonist, nor oxytocin were effective. Collectively, the results imply that VP acts at V1a receptors to excite GABAergic neurons that are presynaptic to a population of magnocellular PVN neurons the identity of which features a unique rebound depolarization. Endogenous sources of VP may be VP-synthesizing neurons in suprachiasmatic nucleus, known to project toward the perinuclear regions of PVN, and/or the magnocellular neurons within PVN.

scholarly journals Dendritic osmosensors modulate activity-induced calcium influx in oxytocinergic magnocellular neurons of the mouse PVN

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Wanhui Sheng ◽  
Scott W Harden ◽  
Yalun Tan ◽  
Eric G Krause ◽  
Charles J Frazier
Keyword(s):  
Ion Channels ◽  
Paraventricular Nucleus ◽  
Calcium Influx ◽  
Optical Recording ◽  
Magnocellular Neurons ◽  
Axon Terminals ◽  
Dendritic Membrane ◽  
Oxytocin Release ◽  
The Relationship ◽  
Existing Data

Hypothalamic oxytocinergic magnocellular neurons have a fascinating ability to release peptide from both their axon terminals and from their dendrites. Existing data indicates that the relationship between somatic activity and dendritic release is not constant, but the mechanisms through which this relationship can be modulated are not completely understood. Here we use a combination of electrical and optical recording techniques to quantify activity-induced calcium influx in proximal vs. distal dendrites of oxytocinergic magnocellular neurons located in the paraventricular nucleus of the hypothalamus (OT-MCNs). Results reveal that the dendrites of OT-MCNs are weak conductors of somatic voltage changes, however activity-induced dendritic calcium influx can be robustly regulated by both osmosensitive and non-osmosensitive ion channels located along the dendritic membrane. Overall, this study reveals that dendritic conductivity is a dynamic and endogenously regulated feature of OT-MCNs that is likely to have substantial functional impact on central oxytocin release.

ANG II-induced excitation of paraventricular nucleus magnocellular neurons: a role for glutamate interneurons

2004 ◽  
Vol 286 (5) ◽  
pp. R894-R902 ◽  
Author(s):  
K. J. Latchford ◽  
A. V. Ferguson
Keyword(s):  
Paraventricular Nucleus ◽  
Kynurenic Acid ◽  
Neuronal Excitability ◽  
Critical Role ◽  
Ang Ii ◽  
Magnocellular Neurons ◽  
Whole Cell Patch Clamp ◽  
Electrolyte Homeostasis ◽  
Hypothalamic Slices

The hypothalamic paraventricular nucleus (PVN) plays a critical role in cardiovascular and neuroendocrine regulation. ANG II (ANG) acts throughout the periphery in the maintenance of fluid-electrolyte homeostasis and has also been demonstrated to act as a neurotransmitter in PVN exerting considerable influence on neuronal excitability in this nucleus. The mechanisms underlying the ANG-mediated excitation of PVN magnocellular neurons have yet to be determined. We have used whole cell patch-clamp techniques in hypothalamic slices to examine the effects of ANG on magnocellular neurons. Application of ANG resulted in a depolarization of magnocellular neurons, a response that was abolished in TTX, suggesting an indirect mechanism of action. Interestingly, ANG also increased the frequency of excitatory postsynaptic potentials/currents in magnocellular neurons, an effect that was abolished after application of the glutamate antagonist kynurenic acid. ANG was without effect on the amplitude of excitatory postsynaptic currents, suggesting a presynaptic action on an excitatory interneuron within PVN. The ANG-induced depolarization was shown to be sensitive to kynurenic acid, revealing the requisite role of glutamate in mediating the ANG-induced excitation of magnocellular neurons. These observations indicate that the ANGergic excitation of magnocellular PVN neurons are dependent on an increase in glutamatergic input and thus highlight the importance of a glutamate interneuron in mediating the effects of this neurotransmitter.

Forced swimming stimulates the expression of vasopressin and oxytocin in magnocellular neurons of the rat hypothalamic paraventricular nucleus

2001 ◽  
Vol 13 (12) ◽  
pp. 2273-2281 ◽  
Author(s):  
Carsten T. Wotjak ◽  
Tetsuro Naruo ◽  
Shinichiro Muraoka ◽  
Renate Simchen ◽  
Rainer Landgraf ◽  
...  
Keyword(s):  
Paraventricular Nucleus ◽  
Forced Swimming ◽  
Hypothalamic Paraventricular Nucleus ◽  
Magnocellular Neurons
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