Search results for "dopamine agonist"
showing 10 items of 48 documents
Implantation is apparently unaffected by the dopamine agonist Cabergoline when administered to prevent ovarian hyperstimulation syndrome in women und…
2007
Background Ovarian hyperstimulation syndrome (OHSS) is a result of ovarian overexpression of vascular endothelial growth factor (VEGF) and its receptor 2 (VEGFR2). VEGF/VEGFR2 binding disrupts cellular junctions and increases vascular permeability (VP), a characteristic of OHSS, but enhances angiogenesis, which is a fundamental step in implantation. In animals, the dopamine agonist Cabergoline (Cb2) prevents VP without affecting angiogenesis. In humans, Cb2 averts OHSS, but a possible detrimental effect on angiogenesis and implantation has not been explored. A pilot study was designed to analyze whether or not Cb2 administration, as a procedure for preventing OHSS, affects the outcome of as…
The 5-HT and alpha-adrenoceptor antagonist effect of four benzylisoquinoline alkaloids on rat aorta.
1998
Abstract The action of four benzylisoquinoline alkaloids (two aporphines—glaucine and apomorphine, a benzylisoquinoline—papaverine and a bisbenzyltetrahydroisoquinoline—antioquine) on 5-HT-induced contraction in rat thoracic aorta has been examined and compared with that of the control drugs: ketanserin, nifedipine, prazosin and phentolamine. The relaxant action on 5-HT-induced contraction was contrasted with that on the contraction induced by noradrenaline and KCl. The results obtained with control drugs show that ketanserin has clear selectivity for 5-HT receptors, whereas prazosin and phentolamine have high selectivity for the α1-adrenoceptor and nifedipine seems to have a more potent ef…
Low-dose dopamine agonist administration blocks vascular endothelial growth factor (VEGF)-mediated vascular hyperpermeability without altering VEGF r…
2006
No specific treatment is available for ovarian hyperstimulation syndrome (OHSS), the most important complication in infertile women treated with gonadotropins. OHSS is caused by increased vascular permeability (VP) through ovarian hypersecretion of vascular endothelial growth factor (VEGF)activating VEGF receptor 2 (VEGFR-2). We previously demonstrated in an OHSS rodent model that increased VP was prevented by inactivating VEGFR-2 with a receptor antagonist(SU5416).However,duetoitstoxicity(thromboembolism) and disruption of VEGFR-2-dependent angiogenic processes critical for pregnancy, this kind of compound cannot be used clinically to prevent OHSS. Dopamine receptor 2 (Dp-r2) agonists, use…
Glycometabolic control in Acromegalic patients with Diabetes: a study of the effects of different treatments for GH excess and for hyperglycaemia.
2012
Background. Diabetes mellitus (DM) is frequently observed in patients with acromegaly. Current therapies for acromegaly may impact glucose regulation, influencing insulin sensitivity and secretion. The question whether these therapies modify control and progression of diabetes once present is still open. Aim. Aim of our study is to analyse glucose control in acromegalic patients with diabetes, evaluating the relation with treatments for GH excess and for diabetes. Methods. Seventy patients with acromegaly and diabetes were studied. Duration and treatments of acromegaly and DM were recorded, together with clinical and metabolic parameters. Results. Most patients (92.8%) were treated with som…
Polysialic acid is required for dopamine D2 receptor-mediated plasticity involving inhibitory circuits of the rat medial prefrontal cortex.
2011
Decreased expression of dopamine D2 receptors (D2R), dysfunction of inhibitory neurotransmission and impairments in the structure and connectivity of neurons in the medial prefrontal cortex (mPFC) are involved in the pathogenesis of schizophrenia and major depression, but the relationship between these changes remains unclear. The polysialylated form of the neural cell adhesion molecule (PSA-NCAM), a plasticity-related molecule, may serve as a link. This molecule is expressed in cortical interneurons and dopamine, via D2R, modulates its expression in parallel to that of proteins related to synapses and inhibitory neurotransmission, suggesting that D2R-targeted antipsychotics/antidepressants…
Dopamine Autoreceptor Agonists in the Treatment of Schizophrenia and Major Depression*
1992
Dopamine autoreceptor agonists reduce the firing rate, synthesis, and release of dopamine in dopaminergic neurons by means of a negative feedback mechanism via stimulation of autoreceptors. Moreover, dopamine autoreceptor agonists are able to stimulate supersensitive but not normosensitive postsynaptic receptors. For dopamine autoreceptor agonists, therapeutic effects by readjustment of excessive or deficient dopaminergic function have been postulated for positive and negative schizophrenic symptomatology as well as for subtypes of depressive disorders. Investigations on the therapeutic effects of autoreceptor-nonselective dopamine agonists in schizophrenia or depression have yielded incons…
Functional feature of a novel model of blood brain barrier: Studies on permeation of test compounds
2001
Drug delivery to the central nervous system (CNS) is subject to the permeability limitations imposed by the blood-brain barrier (BBB). Several systems in vitro have been described to reproduce the physical and biochemical behavior of intact BBB, most of which lack the feature of the in vivo barrier. We developed a fully formed monolayer of RBE4.B immortalized rat brain microvessel endothelial cells (ECs), grown on top of polycarbonate filter inserts with cortical neuronal cells grown on the outside. Neurons induce ECs to synthesize and sort occludin to the cell periphery. Occludin localization is regulated by both compositions of the substratum and soluble signals released by cortical co-cu…
Reduction of red-green discrimination by dopamine D1 receptor antagonists and retinal dopamine depletion
1996
AbstractReduction of wavelength discrimination ability in the 560–640 nm range, but not in the 404–540 nm range, has been demonstrated in goldfish after intravitreal injection of D1-dopamine receptor antagonists. Intravitreal injection of the dopaminergic neurotoxin 6-OH-dopamine severely reduced wavelength discrimination ability in the 540–661 nm range within 3 days. Discrimination ability could be reconstituted by the Dl-agonist SKF 38393. Animals recovered from injection of 6-OH-dopamine within 14–16 days. No change of wavelength discrimination was induced by 6-OH-dopamine in the 461–540 nm range. We conclude that under photopic conditions dopamine modulates retinal mechanisms involved i…
Adjuncts for ovarian stimulation: when do we adopt “orphan indications” for approved drugs?
2009
Several drugs, shown to be safe for other uses, have proven to be highly effective adjuncts for ovarian stimulation. The authors evaluate these "orphan" indications and make recommendations so that more patients will benefit from their use.
Both Short- and Long-Acting D-1/D-2 Dopamine Agonists Induce Less Dyskinesia than l-DOPA in the MPTP-Lesioned Common Marmoset (Callithrix jacchus)
2002
Abstract The current concept of dyskinesia is that pulsatile stimulation of D-1 or D-2 receptors by l -DOPA or short-acting dopamine agonists is more likely to induce dyskinesia compared to long-acting drugs producing more continuous receptor stimulation. We now investigate the ability of two mixed D-1/D-2 agonists, namely pergolide (long-acting) and apomorphine (short-acting), to induce dyskinesia in drug-naive MPTP-lesioned primates, compared to l -DOPA. Adult common marmosets ( Callithrix jacchus ) were lesioned with MPTP (2 mg/kg/day sc for 5 days) and subsequently treated with equieffective antiparkinsonian doses of l -DOPA, apomorphine, or pergolide for 28 days. l -DOPA, apomorphine, …