Biological studies on chimeric dimers of oxytocin and the V2-antagonist, d(CH2)5[D-Ile2, Ile4]arginine vasopressin

2006 ◽  
pp. 643-644
Author(s):  
Jirina Slaninov ◽  
Alena Machov ◽  
Regina Golser ◽  
Lin Chen ◽  
George Barany
Keyword(s):  
Arginine Vasopressin ◽  
Biological Studies ◽  
V2 Antagonist

Chemical Syntheses and Biological Studies on Dimeric Chimeras of Oxytocin and the V2-Antagonist, d(CH2)5[d-Ile2,Ile4]arginine Vasopressin‖,∇

1999 ◽  
Vol 42 (24) ◽  
pp. 5002-5009 ◽  
Author(s):  
Lin Chen ◽  
Regina Golser ◽  
Alena Machová ◽  
Jirina Slaninová ◽  
George Barany
Keyword(s):  
Arginine Vasopressin ◽  
Biological Studies ◽  
V2 Antagonist

Centrally acting vasopressin contributes to endotoxin tolerance

1990 ◽  
Vol 258 (2) ◽  
pp. R443-R449 ◽  
Author(s):  
M. F. Wilkinson ◽  
N. W. Kasting
Keyword(s):  
Escherichia Coli ◽  
Receptor Antagonist ◽  
Arginine Vasopressin ◽  
Endotoxin Tolerance ◽  
Thermoregulatory Response ◽  
Endotoxin Challenge ◽  
E Coli ◽  
Intravenous Injections ◽  
Refractory State ◽  
V2 Antagonist

Repeated daily intravenous injections of bacterial endotoxin induce a refractory state to their usual pyrogenic effects. The neuropeptide arginine vasopressin (AVP) has been implicated in natural fever suppression and may be involved in the process of pyrogenic tolerance to intravenous endotoxin. This study was conducted to test this hypothesis. Tolerance was induced by two successive daily intravenous injections of Escherichia coli endotoxin (50 micrograms/kg) into conscious unrestrained rats. This tolerance was maintained, unaltered, after a third or fourth subsequent injection. However, bilateral administration of an AVP V1-receptor antagonist (0.43-4.3 nmol) into the ventral septal area (VSA) of the rat brain markedly enhanced the thermoregulatory response to a third or fourth endotoxin challenge compared with saline controls. The effect of the V1 antagonist was dose related. In contrast, an AVP V2 antagonist (0.43 nmol) bilaterally injected into the VSA did not affect the tolerant reaction to endotoxin. Furthermore, neither saline nor the V1 antagonist significantly affected core temperature when administered within the VSA without subsequent endotoxin. These results are consistent with the hypothesis that AVP acts as an endogenous antipyretic within the VSA during fever. Moreover, the data suggest a possible role for centrally acting vasopressin during pyrogenic tolerance to E. coli endotoxin.

[Ca2+]i and protein kinase C in vasopressin-induced prostacyclin and ANP release in rat cardiomyocytes

1994 ◽  
Vol 266 (2) ◽  
pp. H597-H605 ◽  
Author(s):  
V. Van der Bent ◽  
D. J. Church ◽  
M. B. Vallotton ◽  
P. Meda ◽  
D. C. Kem ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Arginine Vasopressin ◽  
Cellular Responses ◽  
Rat Cardiomyocytes ◽  
Kinase C ◽  
Transient Rise ◽  
V2 Antagonist ◽  
Pkc Activation ◽  
Membranous Protein

Exposure of cultured, spontaneously beating rat cardiomyocytes to arginine vasopressin (AVP) led to marked increases in the release of prostacyclin (PGI2) and atrial natriuretic peptide (ANP). These responses were accompanied by a rapid, transient rise of cytosolic free Ca2+ concentration ([Ca2+]i) and of membranous protein kinase C (PKC) activity. Ca2+ influx and PKC activity appeared to play important but distinct roles in AVP-induced cellular responses, insofar as only AVP-induced ANP secretion was abolished by the Ca2+ channel antagonist nifedipine, whereas both AVP-induced PGI2 production and ANP release were abolished by the PKC inhibitors staurosporine and CGP-41251. The AVP-induced increase in [Ca2+]i could also be mimicked with the vasopressin (V1-subtype) agonist Octapressin, but not with the V2-agonist 1-desamino-8-D-arginine vasopressin, and was fully abolished by the V1-antagonist [d(CH2)5Tyr(Me)]AVP, but not by d(CH2)5-D-Leu-VAVP (V1-/V2-antagonist). These results indicate that V1-vasopressinergic receptors mediate AVP-induced PGI2 production and ANP secretion in rat cardiomyocytes and that, whereas both Ca2+ influx and PKC activation are required for AVP-induced ANP secretion, AVP-induced PGI2 formation is mainly regulated by PKC.

cAMP and extrarenal vasopressin V2 receptors in dogs

1992 ◽  
Vol 263 (6) ◽  
pp. H1888-H1891 ◽  
Author(s):  
J. F. Liard
Keyword(s):  
Arginine Vasopressin ◽  
Plasma Catecholamines ◽  
Isotonic Saline ◽  
Vena Cava ◽  
Electromagnetic Flowmeter ◽  
Conscious Dogs ◽  
Plasma Camp ◽  
Arterial Plasma ◽  
V2 Antagonist ◽  
Vasopressin Analogues

The effect of vasopressin analogues on plasma adenosine 3',5'-cyclic monophosphate (cAMP) concentration was examined in a group of five conscious dogs instrumented for the measurement of arterial pressure and cardiac output (electromagnetic flowmeter). These dogs were infused for 20 min with a selective antidiuretic (V2) agonist, desamino-8-D-arginine vasopressin (DDAVP, 10 ng.kg-1 x min-1). This infusion was repeated on another day in the presence of the combined V1-V2 antagonist d(CH2)5-D-Tyr(Et)-4-valine,8-arginine vasopressin. The dogs also received an infusion of the selective V1 agonist 2-phenylalanine,8-ornithine oxytocin (Phe-OrnOT) at a rate of 10 ng.kg-1 x min-1. The effect of these infusions was compared with those of an isotonic saline infusion. Plasma cAMP measured in the aorta remained unchanged during all infusions but that of the selective V2 agonist DDAVP alone, during which it increased significantly from 22.4 +/- 0.8 to 32.6 +/- 4.6 and 37.0 +/- 4.1 pmol/ml after 10 and 20 min, respectively. In the plasma sampled from the inferior vena cava caudal to the renal veins, cAMP increased during DDAVP infusion from 22.2 +/- 2.5 to 39.2 +/- 3.8 and 36.0 +/- 4.0 pmol/ml after 10 and 20 min, respectively. The infusion of DDAVP was later given to the same dogs under anesthesia after bilateral nephrectomy, which did not modify the effect of DDAVP on arterial plasma cAMP. In another group of four conscious dogs, infusion of DDAVP at the same rate did not induce significant changes in plasma catecholamines.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Arginine vasopressin modulates electrical activity and calcium homeostasis in pulmonary vein cardiomyocytes

2019 ◽  
Vol 26 (1) ◽  
Author(s):  
Jen-Hung Huang ◽  
Yao-Chang Chen ◽  
Yen-Yu Lu ◽  
Yung-Kuo Lin ◽  
Shih-Ann Chen ◽  
...  
Keyword(s):  
Heart Failure ◽  
Western Blot ◽  
Arginine Vasopressin ◽  
Pulmonary Veins ◽  
Regulatory Proteins ◽  
Electrophysiological Properties ◽  
Beating Rate ◽  
V2 Antagonist ◽  
Underlying Mechanisms

Abstract Background Atrial fibrillation (AF) frequently coexists with congestive heart failure (HF) and arginine vasopressin (AVP) V1 receptor antagonists are used to treat hyponatremia in HF. However, the role of AVP in HF-induced AF still remains unclear. Pulmonary veins (PVs) are central in the genesis of AF. The purpose of this study was to determine if AVP is directly involved in the regulation of PV electrophysiological properties and calcium (Ca2+) homeostasis as well as the identification of the underlying mechanisms. Methods Patch clamp, confocal microscopy with Fluo-3 fluorescence, and Western blot analyses were used to evaluate the electrophysiological characteristics, Ca2+ homeostasis, and Ca2+ regulatory proteins in isolated rabbit single PV cardiomyocytes incubated with and without AVP (1 μM), OPC 21268 (0.1 μM, AVP V1 antagonist), or OPC 41061 (10 nM, AVP V2 antagonist) for 4–6 h. Results AVP (0.1 and 1 μM)-treated PV cardiomyocytes had a faster beating rate (108 to 152%) than the control cells. AVP (1 μM) treated PV cardiomyocytes had higher late sodium (Na+) and Na+/Ca2+ exchanger (NCX) currents than control PV cardiomyocytes. AVP (1 μM) treated PV cardiomyocytes had smaller Ca2+i transients, and sarcoplasmic reticulum (SR) Ca2+ content as well as higher Ca2+ leak. However, combined AVP (1 μM) and OPC 21268 (0.1 μM) treated PV cardiomyocytes had a slower PV beating rate, larger Ca2+i transients and SR Ca2+ content, smaller late Na+ and NCX currents than AVP (1 μM)-treated PV cardiomyocytes. Western blot experiments showed that AVP (1 μM) treated PV cardiomyocytes had higher expression of NCX and p-CaMKII, and a higher ratio of p-CaMKII/CaMKII. Conclusions AVP increases PV arrhythmogenesis with dysregulated Ca2+ homeostasis through vasopressin V1 signaling.

Effect of V2 antagonist on clearance of arginine vasopressin by isolated perfused rat kidneys

1991 ◽  
Vol 261 (3) ◽  
pp. R665-R669 ◽  
Author(s):  
R. Keeler ◽  
A. K. Sato ◽  
J. R. Claybaugh ◽  
N. Wilson
Keyword(s):  
Renal Clearance ◽  
Arginine Vasopressin ◽  
Kidney Cells ◽  
Total Clearance ◽  
Albumin Solution ◽  
Calculated Concentration ◽  
Mean Pressure ◽  
V2 Antagonist ◽  
Made In ◽  
Rat Kidneys

Isolated rat kidneys were perfused with Krebs-Henseleit-bovine serum albumin solution at a mean pressure of 99 +/- 2.6 mmHg. After control periods, arginine vasopressin (AVP) was added to the perfusate at a final calculated concentration of 25 pg/ml (2.5 x 10(-11) M). Urine and perfusate samples were collected at 15-min intervals for the following 60 min to measure kidney function and the renal clearance of immunoreactive AVP (irAVP). At 15-30 min after the addition of AVP, total renal clearance of irAVP was 1,623 +/- 190 microliters.min-1.g kidney wt-1. Glomerular filtration accounted for 35 +/- 3.0% of the total clearance, and 65 +/- 10.3% was cleared by peritubular pathways. Of the filtered irAVP, 48 +/- 4.8% was recovered in the urine. To investigate the importance of V2 receptors in the metabolism of AVP, clearance measurements were made in the presence of the V2 antagonist [d(CH2)5,D-Ile2,Ile4,Arg8]AVP (5 x 10(-9) M). Total renal clearance of irAVP was reduced by 48% to 848 +/- 79 microliters.min-1.g-1. This reduction was entirely accounted for by the complete inhibition of peritubular clearance of irAVP. In the presence of the V2 antagonist, irAVP was cleared only by filtration. The proportion of filtered AVP recovered in the urine (53 +/- 8.7%) was not significantly altered by the presence of the V2 antagonist. We conclude that a major component of the renal clearance of AVP depends on receptor-mediated uptake of AVP in the kidney cells.

Modification of the Electron Microscope for Investigation of Fully Hydrated Biological Specimens

1969 ◽  
Vol 27 ◽  
pp. 418-419 ◽  
Author(s):  
R. C. Moretz ◽  
D. F. Parsons
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Structural Damage ◽  
Lower Percentage ◽  
Vacuum Drying ◽  
Total Removal ◽  
Total Absence ◽  
Biological Studies ◽  
Electron Microscopes ◽  
Beam Damage

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.

Design of Sensitive Photographic Materials for the High-Voltage Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 156-157
Author(s):  
Murray Vernon King ◽  
Donald F. Parsons
Keyword(s):  
Electron Microscope ◽  
Radiation Damage ◽  
High Voltage ◽  
Radiation Sensitivity ◽  
Fast Electrons ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Biological Studies ◽  
Low Sensitivity

Effective application of the high-voltage electron microscope to a wide variety of biological studies has been restricted by the radiation sensitivity of biological systems. The problem of radiation damage has been recognized as a serious factor influencing the amount of information attainable from biological specimens in electron microscopy at conventional voltages around 100 kV. The problem proves to be even more severe at higher voltages around 1 MV. In this range, the problem is the relatively low sensitivity of the existing recording media, which entails inordinately long exposures that give rise to severe radiation damage. This low sensitivity arises from the small linear energy transfer for fast electrons. Few developable grains are created in the emulsion per electron, while most of the energy of the electrons is wasted in the film base.

Sign in / Sign up

Export Citation Format

Share Document