scholarly journals Involvement of Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel 3 in Oxytocin Neuronal Activity in Lactating Rats With Pup Deprivation

ASN NEURO ◽  
2020 ◽  
Vol 12 ◽  
pp. 175909142094465 ◽  
Author(s):  
Dongyang Li ◽  
Haitao Liu ◽  
Xiaoyu Liu ◽  
Hongyang Wang ◽  
Tong Li ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Cyclic Nucleotide ◽  
Brain Slices ◽  
Oxytocin Receptor ◽  
Molecular Association ◽  
Cyclooxygenase 2 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Prostaglandin E ◽  
Western Blots ◽  
Gated Channel

Oxytocin, a hypothalamic neuropeptide essential for breastfeeding, is mainly produced in oxytocin neurons in the supraoptic nucleus (SON) and paraventricular nucleus. However, mechanisms underlying oxytocin secretion, specifically the involvement of hyperpolarization-activated cyclic nucleotide-gated channel 3 (HCN3) in oxytocin neuronal activity, remain unclear. Using a rat model of intermittent and continuous pup deprivation (PD) at the middle stage of lactation, we analyzed the contribution of HCN3 in oxytocin receptor (OTR)-associated signaling cascade to oxytocin neuronal activity in the SON. PD caused maternal depression, anxiety, milk shortage, involution of the mammary glands, and delays in uterine recovery, particularly in continuous PD. PD increased hypothalamic but not plasma oxytocin levels in enzyme-linked immunosorbent assay. In the SON, PD increased c-Fos expression but reduced expressions of cyclooxygenase-2 and HCN3 in Western blots and/or immunohistochemistry. Moreover, PD significantly increased the molecular association of OTR with HCN3 in coimmunoprecipitation. In brain slices, inhibition of HCN3 activity with DK-AH269 blocked prostaglandin E2-evoked increase in the firing activity and burst discharge in oxytocin neurons in patch-clamp recordings. In addition, oxytocin-evoked increase in the molecular association between OTR and HCN3 in brain slices of the SON was blocked by pretreatment with indomethacin, an inhibitor of cyclooxygenase-2. These results indicate that normal activity of oxytocin neurons is under the regulation of an oxytocin receptor–cyclooxygenase-2–HCN3 pathway and that PD disrupts maternal behavior through increasing intranuclear oxytocin secretion in the SON but likely reducing bolus oxytocin release into the blood through inhibition of HCN3 activity.

Decreased Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel 2 Activity in a Rat Model of Absence Epilepsy and the Effect of ZD7288, an Ih Inhibitor, on the Spike-and-Wave Discharges

Pharmacology ◽  
2022 ◽  
pp. 1-8
Author(s):  
Melis Yavuz ◽  
Banu Aydın ◽  
Nihan Çarçak ◽  
Filiz Onat
Keyword(s):  
Rat Model ◽  
Cyclic Nucleotide ◽  
Total Duration ◽  
Absence Epilepsy ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Hcn Channels ◽  
Hcn Channel ◽  
Gated Channel ◽  
Channel Currents

<b><i>Introduction:</i></b> Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel currents of <i>Ih</i> and absence epilepsy seizures are associated, but studies reveal differential results. <b><i>Objective:</i></b> In our study, we aimed to investigate the role of the HCN channels on the expression of spike-and-wave discharges (SWDs) using the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model. <b><i>Methods:</i></b> HCN isoform levels from isolated brains of both naïve nonepileptic Wistar and GAERS groups were evaluated by enzyme-linked immunosorbent assay. ZD7288, an <i>Ih</i> inhibitor as well as an HCN channel antagonist, was administered intracerebroventricularly to the adult GAERS groups, and to evaluate their SWD activities, electroencephalography was recorded. The effect of ZD7288 on the cumulative total duration and number of SWDs and the mean duration of each SWD complex was evaluated. <b><i>Results:</i></b> The HCN2 levels in the cortex and hippocampus of the GAERS group were lower compared to the naïve nonepileptic Wistar group (<i>p</i> &#x3c; 0.05). ZD7288 increased the number of SWDs at the 20th and 120th min with the highest administered dose of 7 μg (<i>p</i> &#x3c; 0.05). <b><i>Conclusion:</i></b> The <i>Ih</i> inhibitor ZD7288 increased the number of SWDs in a genetic absence epilepsy rat model, although this increase may not be significant due to the inconsistent time-dependent effects. In GAERS, the cortical and hippocampal HCN2 channel levels were significantly lower compared to the control group. Further studies are needed with higher doses of ZD7288 to determine if the effects will increase drastically.

Investigating cyclooxygenase-2 signaling in breast cancer-initiating cells.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e21107-e21107
Author(s):  
Carolyn S. Hall ◽  
Andrew Walker ◽  
Barbara A. Laubacher ◽  
Balraj Singh ◽  
Anthony Lucci
Keyword(s):  
Breast Cancer ◽  
Cyclooxygenase 2 ◽  
Receptor Expression ◽  
Prostaglandin E ◽  
Spheroid Formation ◽  
Western Blots ◽  
Ic50 Values ◽  
Cox 2 ◽  
Mcf 7

e21107 Investigating cyclooxygenase-2 signaling in breast cancer-initiating cells Background: Only a small fraction of breast tumor cells, breast cancer-initiating cells (CSC), have the ability to initiate tumor growth and metastasis. Some characteristics of breast CSCs have been described in vitro by employing non-adherent CSC-enriching culture conditions, however, little is known regarding prostanoid signaling or prostaglandin E2 (PgE2) production in CSCs. In this study we measured cyclooxygenase-2 (COX-2) and prostaglandin E2 receptor expression in CSCs and assessed the effects of COX-2 and Ep4 inhibition on in vitro CSC spheroid formation and PgE2 production. Methods: CSCs were cultured in serum-free medium using ultra low attachment plates. Cells were treated with vehicle, a COX-2 inhibitor (Celecoxib), or an EP4 inhibitor (GW627368X) at concentrations of 0.1, 1, 5, 10, 50, or 100uM for 10 days. Spheroids were quantified using a Gelcount machine. Non-linear regression was used to calculate IC50 values. Western blots were performed using anti-COX-2, anti- EP1, 2, 3 and 4 receptor antibodies. Prostaglandin E2 production was measured using a PgE2 immunoassay kit. Results: COX-2 protein expression was observed for MDA-MB-231 and SUM149 CSCs. EP2 and EP4 protein was detected for MCF-7, MDA-MB-231, and SUM149 CSCs. The Celecoxib IC50 values for MCF-7 and SUM149 CSC spheroid formation were 0.5 and 2.2 uM, respectively; GW627386X IC50 values for MCF-7 and SUM149 CSC spheroid formation were 1.2 and 0.3uM, respectively. No significant differences in PGE2 production were observed for MCF-7 CSCs compared to adherent MCF-7 cells (11.5 ± 4.4 vs. 8.7 ± 2.1 pg/mL/106 cells; p=0.88). However, PgE2 production in MDA-MB-231 CSCs was significantly higher than adherent MDA-MB-231 cells (1507.0 ± 329.0 vs. 13.8 ± 5.7 pg/mL/106 cells; p≤0.001) and SUM149 CSC PgE2 production was significantly higher than SUM149 adherent cells (4932.9 ± 501.7 vs. 194.5 ± 31.0 pg/mL/106 cells; p≤0.001). 10uM Celecoxib treatment inhibited PGE2 production in MDA-MB-231 and MDA-MB-231 CSCs. Conclusions: MDA-MB-231 and SUM149 CSCs express COX-2, EP2 and Ep4 and produce high levels of PGE2. CSC spheroid formation is significantly decreased with COX-2 and EP4 inhibition.

Effects of endogenous pyrogen and prostaglandin E2 on hypothalamic neurons in rat brain slices

1987 ◽  
Vol 65 (6) ◽  
pp. 1382-1388 ◽  
Author(s):  
Tatsuo Watanabe ◽  
Akio Morimoto ◽  
Naotoshi Murakami
Keyword(s):  
Prostaglandin E2 ◽  
Rat Brain ◽  
Brain Tissue ◽  
Neuronal Activity ◽  
Brain Slice ◽  
Brain Slices ◽  
Prostaglandin E ◽  
Recording Electrode ◽  
Culture Chamber ◽  
Endogenous Pyrogen

We investigated the effects of endogenous pyrogen and prostaglandin E2 (PGE2) on the preoptic and anterior hypothalamic (POAH) neurons using brain slice preparations from the rat. Partially purified endogenous pyrogen did not change the activities of most of the neurons in the POAH region when applied locally through a micropipette attached to the recording electrode in proximity to the neurons. This indicates that partially purified endogenous pyrogen does not act directly on the neuronal activity in the POAH region. The partially purified endogenous pyrogen, applied into a culture chamber containing a brain slice, facilitated the activities in 24% of the total neurons tested, regardless of the thermal specificity of the neurons. Moreover, PGE2 added to the culture chamber facilitated 48% of the warm-responsive, 33% of the cold-responsive, and 29% of the thermally insensitive neurons. The direction of change in neuronal activity induced by partially purified endogenous pyrogen appears to be almost the same as that induced by PGE2 when these substances were applied by perfusion to the same neuron in the culture chamber. These results suggest that partially purified pyrogen applied to the perfusate of the culture chamber stimulates some constituents of brain tissue to synthesize and release prostaglandin, which in turn affects the neuronal activity of the POAH region.

Expressions of cyclooxygenase-2 (COX-2) and prostaglandin E receptors (EPs) in gallbladder carcinoma (GBca)-association with tumor progression

2001 ◽  
Vol 120 (5) ◽  
pp. A573-A573
Author(s):  
J SHODA ◽  
T ASANO ◽  
T KAWAMOTO ◽  
Y MATSUZAKI ◽  
N TANAKA ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Gallbladder Carcinoma ◽  
Cyclooxygenase 2 ◽  
Prostaglandin E ◽  
Cox 2

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.

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