Search results for "DOPAMINERGIC"

Dopamine autoreceptor agonists in the treatment of schizophrenic disorders

1993

Abstract 1. Synthesis and release of dopamine as well as firing rates of dopaminergic neurons are controlled by stimulation of autoreceptors via a negative feedback regulation, investigations on therapeutic effects of autoreceptor-nonselective dopamine agonists in schizophrenia have yielded inconsistent results. 2. With respect to the dopamine hypothesis of schizophrenia, dopamine autoreceptor agonists have been tested in positive schizophrenic symptomatology in order to reduce the postulated excess of central dopaminergic activity. However, administration of selective dopamine autoreceptor agonists like talipexole or roxindole did not result in a significant improvement of psychopathologic…

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…

Pituitary Function and the Somatotrophic System in Patients with Idiopathic Parkinson’s Disease Under Chronic Dopaminergic Therapy

2007

Idiopathic Parkinson's disease and dopaminergic medication may influence pituitary hormone secretion. The present study aimed to reveal any abnormalities of the somatotrophic system induced by the disease itself and/or the dopaminergic therapy. Investigations of other pituitary hormones under basal and stimulated conditions, as well as an analysis of body composition, were also performed. This was a controlled diagnostic study in which luteinising hormone-releasing hormone, thyroid-releasing hormone, corticotrophin-releasing hormone and arginine hydrochloride were administered to ten patients with idiopathic Parkinson's disease under dopaminergic medication. Basal and stimulated hormone con…

Nuclear Translocation of Nuclear Transcription Factor-κB by α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptors Leads to Transcription of …

2003

We describe a new molecular mechanism of cell death by excitotoxicity mediated through nuclear transcription factor κB (NFκB) in rat embryonic cultures of dopaminergic neurons. Treatment of mesencephalic cultures with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) resulted in a number of changes that occurred selectively in dopaminergic neurons, including persistent elevation in intracellular Ca2+ monitored with Fura-2, and a significant increase in intramitochondrial oxidation of dihydrorhodamine 123, probably associated with transient increase of mitochondrial permeability, cytochrome c release, nuclear translocation of NFκB, and transcriptional activation of the oncogenep53.…

68 Ga‐Labelled Tropane Analogues for the Visualization of the Dopaminergic System

2020

Abstract The development of radiometal‐labelled pharmaceuticals for neuroimaging could offer great potential due to easier handling during labelling and availability through radionuclide generator systems. Nonetheless, to date, no such tracers are available for positron emission tomography, primarily owing to the challenge of crossing the blood–brain barrier (BBB) and loss of affinity through chelator attachment. We have prepared a variety of 68Ga‐labelled phenyltropanes showing that, through a simple hydrocarbon‐linker, it is possible to introduce a chelator onto the lead structure while maintaining its high affinity for hDAT (human dopamine transporter) and simultaneously achieving adequa…

Reelin and CXCL12 regulate distinct migratory behaviors during the development of the dopaminergic system.

2014

The proper functioning of the dopaminergic system requires the coordinated formation of projections extending from dopaminergic neurons in the substantia nigra (SN), ventral tegmental area (VTA) and retrorubral field to a wide array of forebrain targets including the striatum, nucleus accumbens and prefrontal cortex. The mechanisms controlling the assembly of these distinct dopaminergic cell clusters are not well understood. Here, we have investigated in detail the migratory behavior of dopaminergic neurons giving rise to either the SN or the medial VTA using genetic inducible fate mapping, ultramicroscopy, time-lapse imaging, slice culture and analysis of mouse mutants. We demonstrate that…

Dopaminergic agents acting at D1 and D2 receptor sites differently affect melatonin synthesis in rat pineal gland during night.

2001

In vitro affinities of various halogenated benzamide derivatives as potential radioligands for non-invasive quantification of D(2)-like dopamine rece…

2007

Abstract Benzamide derivatives as radiotracers have played an important role in diagnosing malfunction in dopaminergic neurotransmission. A variety of halogenated and two unsubstituted benzamide derivatives were synthesised and their in vitro affinities to dopaminergic, serotonergic and adrenergic receptors and their lipophilicities were determined. As references IBZM (3), raclopride (4) and FLB457 (5) were tested as well. The two iodinated compounds NAE (27) and NADE (28) displayed Ki values of 0.68 and 14 nM for the D2 receptor. The well-established radiotracers FP (1) and DMFP (2) showed affinities in the same range as did the brominated compounds NABrE (29) and NABrDE (30). The log D7.4…

3,4-Dihydroxy- and 3,4-methylenedioxy- phenanthrene-type alkaloids with high selectivity for D2 dopamine receptor.

2013

Abstract Dopamine-mediated neurotransmission plays an important role in relevant psychiatric and neurological disorders. Nowadays, there is an enormous interest in the development of new drugs acting at the dopamine receptors (DR) as potential new targets for the treatment of schizophrenia or Parkinson’s disease. Previous studies have revealed that isoquinoline compounds such as tetrahydroisoquinolines (THIQs) can behave as selective D 2 dopaminergic alkaloids. In the present study we have synthesized five aporphine compounds and five phenanthrene alkaloids and evaluated their potential dopaminergic activity. Binding studies on rat striatal membranes were used to evaluate their affinity and…

Lesions of the dopaminergic innervation of the nucleus accumbens medial shell delay the generation of preference for sucrose, but not of sexual phero…

2011

Male sexual pheromones are rewarding stimuli for female mice, able to induce conditioned place preference. To test whether processing these natural reinforcing stimuli depends on the dopaminergic innervation of the nucleus accumbens, as for other natural rewards, we compare the effects of specific lesions of the dopaminergic innervation of the medial shell of the nucleus accumbens on two different appetitive behaviours, ‘pheromone seeking’ and sucrose preferential intake. Female mice, with no previous experience with either adult male chemical stimuli or with sucrose, received injections of 6-hydroxydopamine (or vehicle) in the medial shell of the accumbens. Then, we analyzed their preferen…