Search results for "Vasopressin"

The Tuberohypophyseal Dopamine System: Dopaminergic Modulation of Vasopressin Release. Characterization of Release and Metabolism of3H-Dopamine

1986

Dopamine (DA) fibres originating in the arcuate nucleus project into the neural and intermediate lobes (N-IL) of the pituitary gland. It has been shown that DA and DA agonists decrease the electrically evoked vasopressin release from the isolated N-IL, an effect antagonized by D2 selective DA antagonists (see Holzbauer et al., 1983). However, there are also observations suggesting that there is an additional facilitation of the evoked vasopressin release via D1 receptors. Thus, SKF 82526 (6-chloro-7,8-drhydroxy-1-(p-hydroxyphenyl)-2,3,4,5-tetrahydro-1H-benzazepine mesylate) concentrationdependently decreased (max. 30 % at 30 nM) and increased (max. 40 % at 3 µM) the electrically evoked vaso…

Non-genomic effects of progesterone on the signaling function of G protein-coupled receptors

1999

Progesterone at concentrations between 10 microM and 200 microM affected the calcium signaling evoked by ligand stimulation of G protein-coupled receptors expressed in several cell lines. At 160 microM progesterone the signaling of all receptors was completely abolished. The effect of progesterone was fast, reversible and was not prevented by cycloheximide indicating its non-genomic nature. Overall, the action of progesterone was more cell type-specific than receptor-specific. Our results are in contrast to a recent report [Grazzini, E., Guillon, G., Mouillac, B. and Zingg, H.H. (1998) Nature 392, 509-512] in which a direct high-affinity interaction between the oxytocin receptor and progest…

Misfolded vasopressin V2 receptors caused by extracellular point mutations entail congenital nephrogenic diabetes insipidus.

2000

Vasopressin V2 receptor mutants from three different patients with congenital nephrogenic diabetes insipidus phenotypes were investigated after expression in COS cells. The amino acid exchanges within the human V2 receptor are located in the second extracellular loop (T204N, Y205C and V206D). Confocal microscopy showed that all receptor mutants were strongly expressed but mainly located within the cell. Residual binding capacity for the antidiuretic hormone arginine vasopressin (AVP) could only be detected for the T204N mutant and was 10-fold lower than for the wild-type receptor. Stimulation of transfected cells with 1 microM AVP showed that the T204N mutant was able to activate the adenyl…

Modifications of the vasopressin and ANP in the rat hypothalamic supraoptic nucleus during and after the physical exercise.

2009

Modifications of atrial natriuretic peptide and vasopressin peptides in the rat hypothalamic supraoptic nucleus during resistance training

2010

Many studies have demonstrated the involvement of atrial natriuretic peptide (ANP) and vasopressin (VP) in the homeostasis of body fluids, but few studies have regarded the hypothalamic magnocellular neurosecretory system during physical exercises. The aim of the present immunohistochemical work is to study the activity of ANP and VP secreting neurons of the hypothalamic supraoptic nucleus during and after resistance training. The study was carried out in Wistar rats trained by a physical resistance-type exercise, using a rung ladder and a varying load fastened to the tail of each rat; the exercise lasted 20 min everyday for periods of 15, 30 and 45 days. Animal groups were sacrificed at th…

Oxytocin and vasopressin expression in the turbinates of patients with chronic sinusitis

2013

Many peptides are present in the nasal mucosa, but few studies have investigated the presence or absence of the oxytocin and vasopressin peptides. This immunohistochemical study on the inferior turbinates of patients affected by chronic sinusitis shows, for the first time, that these peptides are present in the epithelium of both nasal mucosa and glands. Their presence could be related to the presence of atrial natriuretic peptide (ANP), like previously demonstrated in other organs such as heart and prostate, since in some circumstances they play in antagonism.

Agonist and antagonist-dependent internalization of the human vasopressin V2 receptor.

1998

Abstract In this report we demonstrate that in HEK293 cells stably expressing the human V2vasopressin receptor, ligand-induced internalization of the hormone receptor occurs via the clathrin-dependent pathway. Studies of receptor trafficking either by direct visualization of the V2receptor by confocal microscopy or binding experiments show a rapid internalization (half-time 6–7 min). Blocking of the clathrin-dependent pathway by hypertonic sucrose increased vasopressin-induced cellular cAMP production and decreased the desensitization of the V2receptor–adenylyl cyclase system. Thus, internalization appears to be a major regulatory mechanism terminating vasopressin action in HEK293 cells. Tw…

Effects of gadolinium and cadmium on the electrically evoked release of 45calcium from the isolated rat neurohypophysis.

1988

Isolated neural lobes of the rat pituitary gland were fixed by their stalks to a platinum wire electrode. They were loaded with 45calcium and then superfused with radioactivity-free Krebs-solution. The efflux of 45calcium into the superfusion medium was determined. After 54–60 min of superfusion the spontaneous outflow of 45calcium was 2.03%/min of the tissue 45calcium. It was not affected by cadmium (Cd2+, 0.03-3 mmol/1), but reduced by 40% in the presence of 1 mmol/1 gadolinium (Gd3). Electrical stimulation with pulses of 15 Hz (3 times for 1 min with intervals of 1 min) evoked a 45calcium release of 14.4% of the tissue radioactivity. The evoked release of 45calcium was reduced by 80% in …

Correction of the unfavourable effects of vasopressin by nitroglycerin infusion

1982

Nitroglycerin was administered with vasopressin to prevent adverse effects. Vasopressin 0.25U . 70 kg-1 min-1 was infused intravenously in four dogs for 40 minutes, when a venous infusion of nitroglycerin 1.2 micrograms . kg-1 . min-1 was added for 20 minutes. Nitroglycerin 1.2 micrograms . kg-1 . min-1 alone was infused intravenously in another four dogs for 40 minutes. The venous blood pressures (mesenteric and central) and arterial pressures (mesenteric and femoral), the electrocardiogram and arterio-venous difference were recorded. Nitroglycerin was shown to annul the unfavourable effects of vasopressin without altering its efficacy upon portal pressure.

Effects of tetraethylammonium ions on frequency-dependent vasopressin release from the rat neurohypophysis.

1988

1. Isolated rat neurohypophyses were fixed by their stalks to a platinum wire electrode and superfused with oxygenated Krebs-HEPES solution. Vasopressin release into the medium was determined by radioimmunoassay. Vasopressin secretion was increased by electrical stimulation at different frequencies (3-30 Hz) and different train lengths (75-900 pulses). The effects of tetraethylammonium (TEA) ions and of enhanced calcium were tested. 2. Electrical stimulation at 7.5 or 15 Hz evoked a markedly larger release of vasopressin than stimulation at 3 Hz. During continuous stimulation at 7.5 and 15 Hz the evoked vasopressin release per pulse declined rapidly, but with similar time constants for both…