scholarly journals Role of Connexin 36 in Autoregulation of Oxytocin Neuronal Activity in Rat Supraoptic Nucleus

ASN NEURO ◽  
2019 ◽  
Vol 11 ◽  
pp. 175909141984376 ◽  
Author(s):  
Ping Wang ◽  
Stephani C. Wang ◽  
Dongyang Li ◽  
Tong Li ◽  
Hai-Peng Yang ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Supraoptic Nucleus ◽  
Brain Slices ◽  
Virgin Female ◽  
Female Rats ◽  
Dye Coupling ◽  
Connexin 36 ◽  
Postsynaptic Currents ◽  
Junctional Communication ◽  
Vasopressin Neurons

In the supraoptic nucleus (SON), the incidence of dye coupling among oxytocin (OT) neurons increases significantly in nursing mothers. However, the type(s) of connexin (Cx) involved is(are) unknown. In this study, we specifically investigated whether Cx36 plays a functional role in the coupling between OT neurons in the SON of lactating rats. In this brain region, Cx36 was mainly coimmunostained with vasopressin neurons in virgin female rats, whereas in lactating rats, Cx36 was primarily colocalized with OT neurons. In brain slices from lactating rats, application of quinine (0.1 mM), a selective blocker of Cx36, significantly reduced dye coupling among OT neurons as well as the discharge/firing frequency of spikes/action potentials and their amplitude, and transiently depolarized the membrane potential of OT neurons in whole-cell patch-clamp recordings. However, quinine significantly reduced the amplitude, but not frequency, of inhibitory postsynaptic currents in OT neurons; the duration of excitatory postsynaptic currents was reduced but not their frequency and amplitude. Furthermore, the excitatory effect of OT (1 pM) on OT neurons was significantly weakened and delayed by quinine, and burst firing was absent in the presence of this inhibitor. Lastly, Western blotting analysis revealed that the presence of combined, but not alone, quinine and OT significantly reduced the amount of Cx36 in the SON. Thus, Cx36-mediated junctional communication plays a crucial role in autoregulatory control of OT neuronal activity, likely by acting at the postsynaptic sites. The level of Cx36 is modulated by its own activity and the presence of OT.

scholarly journals Circulating Secretin Activates Supraoptic Nucleus Oxytocin and Vasopressin Neurons via Noradrenergic Pathways in the Rat

Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2681-2688 ◽  
Author(s):  
Sathya Velmurugan ◽  
Paula J. Brunton ◽  
Gareth Leng ◽  
John A. Russell
Keyword(s):  
Amino Acid ◽  
Firing Rate ◽  
Noradrenaline Release ◽  
Supraoptic Nucleus ◽  
Female Rats ◽  
Adrenoceptor Antagonist ◽  
Intracerebroventricular Infusion ◽  
Neuroendocrine Neurons ◽  
Vasopressin Neurons

Secretin is a 27-amino acid brain-gut peptide from duodenal S-cells. We tested the effects of systemic administration of secretin to simulate its postprandial release on neuroendocrine neurons of the supraoptic nucleus (SON) in urethane-anesthetized female rats. Secretin dose-dependently increased the firing rate of oxytocin neurons, more potently than cholecystokinin, and dose-dependently increased plasma oxytocin concentration. The effect of secretin on SON vasopressin neurons was also predominantly excitatory, in contrast to the inhibitory actions of cholecystokinin. To explore the involvement of noradrenergic inputs in secretin-induced excitation, benoxathian, an α1-adrenoceptor antagonist, was infused intracerebroventricularly. Benoxathian intracerebroventricular infusion blocked the excitation by secretin of both oxytocin and vasopressin neurons. To test the role of local noradrenaline release in the SON, benoxathian was microdialyzed onto the SON. The basal firing rate of oxytocin neurons was slightly reduced and the secretin-induced excitation was attenuated during benoxathian microdialysis. Hence, noradrenergic pathways mediate the excitation by systemic secretin of oxytocin neurons via α1-adrenoceptors in the SON. As both systemic secretin and oxytocin are involved in regulating gastrointestinal functions and natriuresis, systemically released secretin might act partly through oxytocin.

Activation of adenosine A2A receptors alters postsynaptic currents and depolarizes neurons of the supraoptic nucleus

2006 ◽  
Vol 291 (2) ◽  
pp. R359-R366 ◽  
Author(s):  
Todd A. Ponzio ◽  
Yu-Feng Wang ◽  
Glenn I. Hatton
Keyword(s):  
Supraoptic Nucleus ◽  
Cell Activity ◽  
Brain Slices ◽  
Cell Types ◽  
Receptor Activation ◽  
A2a Receptors ◽  
Postsynaptic Currents ◽  
Cgs 21680 ◽  
Whole Cell Patch Clamp ◽  
Sites Of Action

Supraoptic nucleus (SON) neurons secrete oxytocin or vasopressin in response to various physiological stimuli (e.g., lactation/suckling, dehydration). Released near fenestrated capillaries of the neurohypophysis, these peptides enter the blood and travel to peripheral target organs. The pervasive neuromodulator adenosine, acting at A1 receptors, is an important inhibitory regulator of magnocellular neuroendocrine cell activity. Another high-affinity adenosine receptor exists in this system, however. We examined the physiological effects of adenosine A2A receptor activation and determined its localization among various cell types within the SON. In whole cell patch-clamp recordings from rat brain slices, application of the selective adenosine A2A receptor agonist CGS-21680 caused membrane depolarizations in SON neurons, often leading to increased firing activity. Membrane potential changes were persistent (>10 min) and could be blocked by the selective A2A receptor antagonist ZM-241385, or GDP-β-S, the latter suggesting postsynaptic sites of action. However, ±-α-methyl-(4-carboxyphenyl)glycine or TTX also blocked CGS-21680 effects, indicating secondary actions on postsynaptic neurons. In voltage-clamp mode, application of CGS-21680 caused a slight increase (∼8%) in high-frequency clusters of excitatory postsynaptic currents. With the use of specific antibodies, adenosine A2A receptors were immunocytochemically localized to both the magnocellular neurons and astrocytes of the SON. Ecto-5′nucleotidase, an enzyme involved in the metabolism of ATP to adenosine, was also localized to astrocytes of the SON. These results demonstrate that adenosine acting at A2A receptors can enhance the excitability of SON neurons and modulate transmitter release from glutamatergic afferents projecting to the nucleus. We suggest that adenosine A2A receptors may function in neuroendocrine regulation through both direct neuronal mechanisms and via actions involving glia.

scholarly journals Dendritic Projections and Dye-Coupling in Dopaminergic Neurons of the Substantia Nigra Examined in Horizontal Brain Slices From Young Rats

2003 ◽  
Vol 90 (4) ◽  
pp. 2531-2535 ◽  
Author(s):  
John Y. Lin ◽  
Michiel van Wyk ◽  
Tharushini K. Bowala ◽  
Min-Yau Teo ◽  
Janusz Lipski
Keyword(s):  
Substantia Nigra ◽  
Dopaminergic Neurons ◽  
Lucifer Yellow ◽  
Brain Slices ◽  
Positive Control ◽  
Substantia Nigra Pars Compacta ◽  
Dye Coupling ◽  
Whole Cell ◽  
Connexin 36

We examined the rostro-caudal dendritic spread of striatally projecting dopaminergic neurons of the Substantia Nigra pars compacta (SNc) and investigated the presence of dye-coupling after labeling these cells with a mixture of lucifer yellow (LY) and neurobiotin (NB) or with LY alone. Whole cell recordings were made from horizontal brain slices (400 μm) obtained from P5-P20 rats. SNc neurons retrogradely labeled with Fluoro-Gold and located in the region containing tyrosine hydroxylase-immunoreactive cells displayed Ih current and other properties characteristic of SNc neurons. To prevent extracellular leakage, dyes were introduced into patch pipettes after the establishment of whole cell configuration, and cells were filled under visual control. In contrast to previous studies conducted in coronal sections that identified dendritic projections of SNc neurons mainly in the medio-lateral and ventral directions, almost all neurons labeled in our study (53/54) additionally displayed a large rostro-caudal dendritic span (649 ± 219 μm). Dye-coupling between SNc neurons was not observed under basal conditions, in the presence of gap junction “openers” (forskolin, trimethylamine), or after neurons were filled with LY using sharp intracellular microelectrodes. As a “positive control,” dye-coupling was demonstrated in four hippocampal dentate gyrus neurons that were filled using the same patch pipette technique. In addition, none of the tested SNc cells ( n = 12) showed expression of connexin 36 (the “neuronal” connexin) when tested with single-cell RT-PCR. In conclusion, this study revealed extensive rostro-caudal dendritic projections of SNc neurons. Under our in vitro conditions, no evidence was found for dye-coupling among these neurons.

Estrogen-induced modulation of hypothalamic osmoregulation in female rats

1990 ◽  
Vol 258 (4) ◽  
pp. R924-R929 ◽  
Author(s):  
T. Akaishi ◽  
Y. Sakuma
Keyword(s):  
Neuronal Activity ◽  
Supraoptic Nucleus ◽  
Water Retention ◽  
Brain Slice ◽  
Plasma Osmolality ◽  
Estrogen Treatment ◽  
Female Rats ◽  
Neuronal Activation ◽  
Animal Preparation ◽  
Vasopressinergic Neurons

Estrogen treatment of ovariectomized female rats for a week decreased plasma osmolality from 294 to 278 mosmol/kgH2O, but recordings from the whole animal preparation under urethan anesthesia failed to detect any change in the activity of 76 vasopressinergic neurons in the supraoptic nucleus (SON) of the hypothalamus. In brain slice preparations, neuronal discharge of 74 presumed vasopressinergic SON cells increased linearly as the osmolality of the perfusate was increased from 278 to 320 mosmol/kgH2O, each 10 mosmol/kgH2O fraction corresponding to a 0.7-Hz change. This osmolality-neuronal activity relationship was similar in the slices taken from the estrogen-treated and the control ovariectomized animals, except that the neurons in the former fired twice as frequently as those in the control throughout the osmolality range. This difference explains the estrogen-induced decrease in the osmolality threshold to elicit antidiuresis and the resultant water retention in estrogen-treated animals. It was reasoned that the estrogen-induced neuronal activation was offset by the decreased plasma osmolality in the animal as a whole.

Basal Lamina Formation in DMBA Induced Mammary Carcinoma

1977 ◽  
Vol 35 ◽  
pp. 534-535
Author(s):  
I. Russo ◽  
J. Saby ◽  
J. Russo
Keyword(s):  
Mammary Carcinoma ◽  
Virgin Female ◽  
Mammary Glands ◽  
Sesame Oil ◽  
Female Rats ◽  
Ultrastructural Changes ◽  
Post Inoculation ◽  
Intermediate Type ◽  
Sprague Dawley ◽  
Intercellular Spaces

It has been previously demonstrated that DMBA-induced rat mammary carcinoma originates in the terminal end bud (TEB) of the mammary gland by proliferation of intermediate type cells (1). The earliest lesion identified is the intraductal proliferation (IDP), which gives rise to intraductal carcinomas. These evolve to cribriform, papillary and comedo types (2). In the present work, we report the ultrastructural changes that take place in the IDP for the formation of a cribriform pattern.Fifty-five-day-old Sprague Dawley virgin female rats were inoculated intra- gastrically with 20 mg 7,12-dimethylbenz(a)anthracene (DMBA) in 1 ml sesame oil. Non-inoculated, age-matched females were used as controls. Mammary glands from both control and experimental rats were removed weekly from the time of inoculation until 86 days post-inoculation. The glands were fixed and processed for electron microscopy (2).The first change observed in IDP's was the widening of intercellular spaces and the secretion of an electron dense material into these spaces (Fig. 1).

Ultrastructural Changes in the Mammary Epithelial Cell Population During Neoplastic Development Induced by A Chemical Carcinogen.

1976 ◽  
Vol 34 ◽  
pp. 250-251 ◽  
Author(s):  
J. Russo ◽  
W. Isenberg ◽  
M. Ireland ◽  
I.H. Russo
Keyword(s):  
Mammary Gland ◽  
Cell Population ◽  
Virgin Female ◽  
Histological Change ◽  
Mammary Epithelial ◽  
Female Rats ◽  
Ultrastructural Changes ◽  
Post Inoculation ◽  
Chemical Carcinogen ◽  
Sprague Dawley

The induction of rat mammary carcinoma by the chemical carcinogen DMBA is used as a model for the study of the human disease (1). We previously described the histochemical changes that occur in the mammary gland of DMBA treated animals before the earliest manifested histological change, the intraductal proliferation (IDP), was observed (2). In the present work, we demonstrate that a change in the stable cell population found in the resting mammary gland occurs after carcinogen administration.Fifty-five day old Sprague-Dawley virgin female rats were inoculated intragastrically with 20mg of 7,12-dimethylbenz(a)anthracene (DMBA) in 1ml sesame oil. Non-inoculated, age-matched females were used as controls. Mammary glands from control and inoculated rats were removed weekly from the time of inoculation until 60 days post-inoculation. For electron microscopy, the glands were immersed in Karnovsky's fixative, post-fixed in 1% OsO4, dehydrated, and embedded in an Epon-Araldite mixture. Thick (lμ) sections were stained with 1% toluidine blue and were used for selecting areas for ultrastructural study.

scholarly journals Difluoroboron β-diketonate polylactic acid oxygen nanosensors for intracellular neuronal imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meng Zhuang ◽  
Suchitra Joshi ◽  
Huayu Sun ◽  
Tamal Batabyal ◽  
Cassandra L. Fraser ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Oxygen Sensing ◽  
Brain Slices ◽  
Neuronal Cell ◽  
Quantum Yields ◽  
Poly Lactic Acid ◽  
Neuronal Cultures ◽  
Primary Neuronal Cultures ◽  
Non Invasive ◽  
Mitotracker Red

AbstractCritical for metabolism, oxygen plays an essential role in maintaining the structure and function of neurons. Oxygen sensing is important in common neurological disorders such as strokes, seizures, or neonatal hypoxic–ischemic injuries, which result from an imbalance between metabolic demand and oxygen supply. Phosphorescence quenching by oxygen provides a non-invasive optical method to measure oxygen levels within cells and tissues. Difluoroboron β-diketonates are a family of luminophores with high quantum yields and tunable fluorescence and phosphorescence when embedded in certain rigid matrices such as poly (lactic acid) (PLA). Boron nanoparticles (BNPs) can be fabricated from dye-PLA materials for oxygen mapping in a variety of biological milieu. These dual-emissive nanoparticles have oxygen-insensitive fluorescence, oxygen-sensitive phosphorescence, and rigid matrix all in one, enabling real-time ratiometric oxygen sensing at micron-level spatial and millisecond-level temporal resolution. In this study, BNPs are applied in mouse brain slices to investigate oxygen distributions and neuronal activity. The optical properties and physical stability of BNPs in a biologically relevant buffer were stable. Primary neuronal cultures were labeled by BNPs and the mitochondria membrane probe MitoTracker Red FM. BNPs were taken up by neuronal cell bodies, at dendrites, and at synapses, and the localization of BNPs was consistent with that of MitoTracker Red FM. The brain slices were stained with the BNPs, and the BNPs did not significantly affect the electrophysiological properties of neurons. Oxygen maps were generated in living brain slices where oxygen is found to be mostly consumed by mitochondria near synapses. Finally, the BNPs exhibited excellent response when the conditions varied from normoxic to hypoxic and when the neuronal activity was increased by increasing K+ concentration. This work demonstrates the capability of BNPs as a non-invasive tool in oxygen sensing and could provide fundamental insight into neuronal mechanisms and excitability research.

scholarly journals Casein Kinase 2 dependent phosphorylation of eIF4B regulates BACE1 expression in Alzheimer’s disease

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Barbara Bettegazzi ◽  
Laura Sebastian Monasor ◽  
Serena Bellani ◽  
Franca Codazzi ◽  
Lisa Michelle Restelli ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neuronal Activity ◽  
Neurodegenerative Disorder ◽  
Brain Slices ◽  
Casein Kinase ◽  
Casein Kinase 2 ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Bace1 Expression

AbstractAlzheimer’s disease (AD) is the most common age-related neurodegenerative disorder. Increased Aβ production plays a fundamental role in the pathogenesis of the disease and BACE1, the protease that triggers the amyloidogenic processing of APP, is a key protein and a pharmacological target in AD. Changes in neuronal activity have been linked to BACE1 expression and Aβ generation, but the underlying mechanisms are still unclear. We provide clear evidence for the role of Casein Kinase 2 in the control of activity-driven BACE1 expression in cultured primary neurons, organotypic brain slices, and murine AD models. More specifically, we demonstrate that neuronal activity promotes Casein Kinase 2 dependent phosphorylation of the translation initiation factor eIF4B and this, in turn, controls BACE1 expression and APP processing. Finally, we show that eIF4B expression and phosphorylation are increased in the brain of APPPS1 and APP-KI mice, as well as in AD patients. Overall, we provide a definition of a mechanism linking brain activity with amyloid production and deposition, opening new perspectives from the therapeutic standpoint.

scholarly journals Activity-Dependent Modulation of Neurotransmitter Innervation to Vasopressin Neurons of the Supraoptic Nucleus

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 348-354 ◽  
Author(s):  
Nancy K. Mueller ◽  
Shi Di ◽  
Charles M. Paden ◽  
James P. Herman
Keyword(s):  
Glutamic Acid ◽  
Glutamic Acid Decarboxylase ◽  
Supraoptic Nucleus ◽  
Glutamate Transporter ◽  
Acid Decarboxylase ◽  
Vesicular Glutamate Transporter ◽  
Salt Loading ◽  
Synaptic Boutons ◽  
Vasopressin Neurons ◽  
Activity Dependent

Confocal microscopy was used to assess activity-dependent neuroplasticity in neurotransmitter innervation of vasopressin immunoreactive magnocellular neurons in the supraoptic nucleus (SON). Vesicular glutamate transporter 2, glutamic acid decarboxylase, and dopamine β-hydroxylase (DBH) synaptic boutons were visualized in apposition to vasopressin neurons in the SON. A decrease in DBH synaptic boutons per cell was seen upon salt loading, indicating diminished noradrenergic/adrenergic innervation. Loss of DBH appositions to vasopressin neurons was associated with a general loss of DBH immunoreactivity in the SON. In contrast, the number of vesicular glutamate transporter 2 synaptic boutons per neuron increased with salt loading, consistent with increased glutamatergic drive of magnocellular SON neurons. Salt loading also caused an increase in the total number of glutamic acid decarboxylase synaptic boutons on vasopressinergic neurons, suggesting enhanced inhibitory innervation as well. These studies indicate that synaptic plasticity compensates for increased secretory demand and may indeed underlie increased secretion, perhaps via neurotransmitter-specific, activity-related changes in synaptic contacts on vasopressinergic magnocellular neurons in the SON.

scholarly journals Effects of L-arginine oral supplements in pregnant spontaneously hypertensive rats

2006 ◽  
Vol 21 (4) ◽  
pp. 192-196 ◽  
Author(s):  
José Ricardo Sousa Ayres de Moura ◽  
Nelson Sass ◽  
Sérgio Botelho Guimarães ◽  
Paulo Roberto Leitão de Vasconcelos ◽  
Rosiane Mattar ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Statistical Significance ◽  
Virgin Female ◽  
Female Rats ◽  
Vaginal Smear ◽  
Shr Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Oral Supplementation

PURPOSE: To evaluate the effects of L-arginine oral supplementation in spontaneously hypertensive pregnant rats (SHR). METHODS: Thirty SHR and ten Wistar-EPM-1 virgin female rats were used in the study. Before randomization, females were caged with males of the same strain (3:1). Pregnancy was confirmed by sperm-positive vaginal smear (Day 0). Wistar-EPM-1 rats served as counterpart control (C-1). SHR rats were randomized in 4 groups (n=10): Group Control 2, non-treated rats; Group L-Arginine treated with L-arginine 2%; Group Alpha-methyldopa treated with Alpha-methyldopa 33mg/Kg; Group L-Arginine+Alpha-methyldopa treated with L-arginine 2%+Alpha-methyldopa 33mg/Kg. L-arginine 2% solution was offered ad libitum in drinking water and Alpha-methyldopa was administered by gavage twice a day during the length of pregnancy (20 days). Blood pressure was measured by tailcuff plethysmography on days 0 and 20. Body weight was measured on days 0, 10 and 20. Results were expressed as mean ± SD (Standard Deviation). One-Way ANOVA/Tukey (or Kruskal-Wallis/Dunn, as appropriate) was used for group comparisons. Statistical significance was accepted as p<0.05. RESULTS: There was no significant weight gain in isolated L-arginine treated SHR. Mean blood pressure decreased in L-arginine-treated SLR compared with untreated-SHR rats. CONCLUSION: L-arginine oral supplementation reduces blood pressure in spontaneously hypertensive rats during pregnancy.

Sign in / Sign up

Export Citation Format

Share Document