Effects of inactivation of oxytocin receptor and inhibition of prostaglandin synthesis on uterine oxytocin receptor and gap junction formation and labor in the rat

1991 ◽  
Vol 69 (9) ◽  
pp. 1262-1267 ◽  
Author(s):  
W. Y. Chan ◽  
Irene Berezin ◽  
E. E. Daniel ◽  
K. C. Russell ◽  
Victor J. Hruby
Keyword(s):  
Gap Junction ◽  
Naproxen Sodium ◽  
Critical Role ◽  
Treated Group ◽  
Oxytocin Receptor ◽  
Prostaglandin Synthesis ◽  
Pregnant Rats ◽  
Junction Formation ◽  
Inhibition Of Prostaglandin Synthesis ◽  
Oxytocin Antagonist

Normal term labor is associated with a surge in myometrial oxytocin receptor formation and gap junction development. We have previously shown that inhibition of prostaglandin synthesis by naproxen sodium, 2.0 mg/day, suppressed oxytocin receptor formation but not gap junction formation and prolonged gestation. In this study, we investigated the effects of a specific oxytocin antagonist on oxytocin receptor formation, gap junction formation, and labor in the rat. [Pen1Phe(Me)2,Thr4,Orn8]oxytocin, a specific oxytocin antagonist, was infused subcutaneously during the last 3 days of pregnancy at 300 μg/day. Measurements of myometrial oxytocin receptor concentrations and gap junction formation on days 21 and 22 and days 22–23 (in labor) pregnant uteri showed no significant differences in the Bmax and Kd values between the control and the treated group. Gestation period was not prolonged by the oxytocin antagonist. However, in a separate group of day 23 pregnant rats, the uterine contractile response to 60 mU of oxytocin i.v. was found completely blocked by 10 μg of the oxytocin antagonist. These findings suggest that although functional oxytocin receptors did not appear to be essential for the initiation of labor, oxytocin antagonists may still be effective in the prevention of premature contractions. We also examined the effects of a higher dose of naproxen sodium, 5.0 mg/day, on gap junction formation. At this dose, naproxen sodium suppressed both oxytocin receptor and gap junction formation, prolonged gestation, and delayed parturition by 24 h or longer. Prostaglandin appears to be an important regulator or mediator of oxytocin receptor and gap junction formation and plays a critical role in the initiation of labor.Key words: oxytocin, prostaglandin, oxytocin receptor, gap junction, labor.

Gap junction formation and regulation in myometrium

1980 ◽  
Vol 239 (5) ◽  
pp. C217-C228 ◽  
Author(s):  
R. E. Garfield ◽  
D. Merrett ◽  
A. K. Grover
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
High Frequency ◽  
Actinomycin D ◽  
Low Frequency ◽  
Synthesis Inhibitor ◽  
Pregnant Rats ◽  
Junction Formation ◽  
Prostacyclin Analog

Myometrial tissues from pregnant rats were examined by electron microscopy for the presence of gap junctions after incubation in vitro with a variety of agents. Gap junctions were present in low frequency or absent prior to incubation in vitro. The junctions were present in control tissues in high frequency after 48 h incubation. The addition of cycloheximide or actinomycin D inhibited the incorporation of [3H]leucine into TCA-precipitable proteins and prevented gap junction formation. A prostacyclin analog (carbacyclin), a thromboxane synthesis inhibitor, and indomethacin also prevented gap junction formation. Oxytocin had no effect on gap junction formation but isoxsuprine decreased their number and increased their size. Isoxsuprine and isoproterenol also produced electron opaque crystals associated with the gap junctions. Dibutyryl cAMP treatment but not monobutyryl cGMP also increased the size of gap junctions. Based upon this and previous studies, we propose at least four sites for regulation of gap junctions and possible control of labor.

Antipyretic Activity of the Root Extracts of Xylocarpus

2019 ◽  
Vol 9 (3) ◽  
pp. 35-38
Author(s):  
Ganesh Kumar Y ◽  
Pranitha D ◽  
Phaneendra D ◽  
Madhava Reddy Ch
Keyword(s):  
Mechanisms Of Action ◽  
Prostaglandin Synthesis ◽  
The Body ◽  
Human Race ◽  
Pharmacological Activities ◽  
Standard Drug ◽  
Root Extracts ◽  
Antipyretic Activity ◽  
Inhibition Of Prostaglandin Synthesis ◽  
Elevated Body Temperature

Various types of conditions exist in the body that causes fever and pain. Drugs that are used to treat fever are called antipyretics, and those are usually prescribed to treat elevated body temperature. But those drugs result in many other side effects like ulcers, perforations, bleedings and obstructions, which make their use questionable and limiting. Medicinal plants are used in the treatment of diseases from the starting of the human race and the process; they had been subjected to rigorous investigations and tests to establish a scientific proof and validation of the various pharmacological activities and their respective mechanisms of action in treating the herbs. Considering the anti-inflammatory properties of the plant, Xylocarpus mekongesis was investigated for its antipyretic activity in yeast method and 3doses out of which 00mg/kg body weight showed a better activity compared to the standard drug and other extracts too. The mechanism of action was similar to the paracetamol action that is inhibition of prostaglandin synthesis.

scholarly journals Opening Hemichannels in Nonjunctional Membrane Stimulates Gap Junction Formation

2004 ◽  
Vol 86 (2) ◽  
pp. 781-796 ◽  
Author(s):  
Derek L. Beahm ◽  
James E. Hall
Keyword(s):  
Gap Junction ◽  
Junction Formation

Propofol Attenuated Acute Kidney Injury after Orthotopic Liver Transplantation via Inhibiting Gap Junction Composed of Connexin 32

2015 ◽  
Vol 122 (1) ◽  
pp. 72-86 ◽  
Author(s):  
Chenfang Luo ◽  
Dongdong Yuan ◽  
Xiaoyun Li ◽  
Weifeng Yao ◽  
Gangjian Luo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Liver Transplantation ◽  
Acute Kidney Injury ◽  
Gap Junction ◽  
Orthotopic Liver Transplantation ◽  
Critical Role ◽  
Kidney Injury ◽  
Cellular Injury ◽  
Knock Down ◽  
Hypoxia Reoxygenation

Abstract Background: Postliver transplantation acute kidney injury (AKI) severely affects patient survival, whereas the mechanism is unclear and effective therapy is lacking. The authors postulated that reperfusion induced enhancement of connexin32 (Cx32) gap junction plays a critical role in mediating postliver transplantation AKI and that pretreatment/precondition with the anesthetic propofol, known to inhibit gap junction, can confer effective protection. Methods: Male Sprague–Dawley rats underwent autologous orthotopic liver transplantation (AOLT) in the absence or presence of treatments with the selective Cx32 inhibitor, 2-aminoethoxydiphenyl borate or propofol (50 mg/kg) (n = 8 per group). Also, kidney tubular epithelial (NRK-52E) cells were subjected to hypoxia–reoxygenation and the function of Cx32 was manipulated by three distinct mechanisms: cell culture in different density; pretreatment with Cx32 inhibitors or enhancer; Cx32 gene knock-down (n = 4 to 5). Results: AOLT resulted in significant increases of renal Cx32 protein expression and gap junction, which were coincident with increases in oxidative stress and impairment in renal function and tissue injury as compared to sham group. Similarly, hypoxia–reoxygenation resulted in significant cellular injury manifested as reduced cell growth and increased lactate dehydrogenase release, which was significantly attenuated by Cx32 gene knock-down but exacerbated by Cx32 enhancement. Propofol inhibited Cx32 function and attenuated post-AOLT AKI. In NRK-52E cells, propofol reduced posthypoxic reactive oxygen species production and attenuated cellular injury, and the cellular protective effects of propofol were reinforced by Cx32 inhibition but cancelled by Cx32 enhancement. Conclusion: Cx32 plays a critical role in AOLT-induced AKI and that inhibition of Cx32 function may represent a new and major mechanism whereby propofol reduces oxidative stress and subsequently attenuates post-AOLT AKI.

scholarly journals Decreased connexin43 expression in the mouse heart potentiates pacing-induced remodeling of repolarizing currents

2008 ◽  
Vol 295 (5) ◽  
pp. H1905-H1916 ◽  
Author(s):  
Andrianos Kontogeorgis ◽  
Xiaodong Li ◽  
Eunice Y. Kang ◽  
Jonathan E. Feig ◽  
Marc Ponzio ◽  
...  
Keyword(s):  
Gap Junction ◽  
Ventricular Myocytes ◽  
Critical Role ◽  
Mouse Heart ◽  
Wild Type ◽  
Short Term ◽  
Wild Type Littermate ◽  
Cx43 Expression ◽  
Significant Prolongation ◽  
Electrophysiological Effects

Gap junction redistribution and reduced expression, a phenomenon termed gap junction remodeling (GJR), is often seen in diseased hearts and may predispose toward arrhythmias. We have recently shown that short-term pacing in the mouse is associated with changes in connexin43 (Cx43) expression and localization but not with increased inducibility into sustained arrhythmias. We hypothesized that short-term pacing, if imposed on murine hearts with decreased Cx43 abundance, could serve as a model for evaluating the electrophysiological effects of GJR. We paced wild-type (normal Cx43 abundance) and heterozygous Cx43 knockout (Cx43+/−; 66% mean reduction in Cx43) mice for 6 h at 10–15% above their average sinus rate. We investigated the electrophysiological effects of pacing on the whole animal using programmed electrical stimulation and in isolated ventricular myocytes with patch-clamp studies. Cx43+/− myocytes had significantly shorter action potential durations (APD) and increased steady-state ( Iss) and inward rectifier ( IK1) potassium currents compared with those of wild-type littermate cells. In Cx43+/− hearts, pacing resulted in a significant prolongation of ventricular effective refractory period and APD and significant diminution of Iss compared with unpaced Cx43+/− hearts. However, these changes were not seen in paced wild-type mice. These data suggest that Cx43 abundance plays a critical role in regulating currents involved in myocardial repolarization and their response to pacing. Our study may aid in understanding how dyssynchronous activation of diseased, Cx43-deficient myocardial tissue can lead to electrophysiological changes, which may contribute to the worsened prognosis often associated with pacing in the failing heart.

scholarly journals THE EFFECT OF INHIBITION OF PROSTAGLANDIN SYNTHESIS ON OVARIAN HYPERTROPHY IN THE RAT

Reproduction ◽  
1975 ◽  
Vol 44 (3) ◽  
pp. 473-479 ◽  
Author(s):  
V. D. CASTRACANE ◽  
L. F. TANKENOW ◽  
A. A. SHAIKH
Keyword(s):  
Prostaglandin Synthesis ◽  
Inhibition Of Prostaglandin Synthesis
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