Search results for "dopamine"
showing 10 items of 660 documents
Influence of ventral tegmental area (A10 region) on flight behaviour elicited by hypothalamic stimulation in the cat.
1993
The influence of the ventral tegmental area (VTA) (dopaminergic A10 group neurons) on flight behaviour, induced by hypothalamic stimulation, was studied in the cat. Co-stimulation of hypothalamus and VTA (ipsi- or contralateral) induced an increase of the flight latency. Slow-motion analysis of flight behaviour showed that this increase was due to the augmentation of the fixation latency (FL) whereas the upright latency (UL) was not modified. Sulpiride injection (50 mg/kg i.p.) provoked the disappearance of VTA effect without affecting the basal behavioural sequence. The results show that DA A10 group neurons increase the attentive component of the flight reaction, suggesting a possible inf…
Effect of halloysite nanotubes filler on polydopamine properties
2019
Abstract Hypothesis Polydopamine (PDA) is widely used as hydrophilic coating for several applications. However, most of the methods studied to improve or manipulate PDA properties are multistep and time-consuming, and there is a need for versatile strategies aimed at controlling and modifying the properties of PDA. Experiments PDA-halloysite nanocomposites were produced under different oxidation conditions in alkaline and acidic media and were characterized by UV–visible and attenuated total refraction- Fourier Transform Infrared spectroscopies, thermogravimetric analysis, porosimetry, scanning electron microscopy, X-ray diffraction and contact angle measurements against the reference PDA p…
D2R striatopallidal neurons inhibit both locomotor and drug reward processes.
2009
The specific functions of dopamine D(2) receptor-positive (D(2)R) striatopallidal neurons remain poorly understood. Using a genetic mouse model, we found that ablation of D(2)R neurons in the entire striatum induced hyperlocomotion, whereas ablation in the ventral striatum increased amphetamine conditioned place preference. Thus D(2)R striatopallidal neurons limit both locomotion and, unexpectedly, drug reinforcement.
Switch between tyrosinase and catecholoxidase activity of scorpion hemocyanin by allosteric effectors
2008
AbstractPhenoloxidases and hemocyanins have similar type 3 copper centers although they perform different functions. Hemocyanins are oxygen carriers, while phenoloxidases (tyrosinase/catecholoxidase) catalyze the initial step in melanin synthesis. Tyrosinases catalyze two subsequent reactions, whereas catecholoxidases catalyze only the second one. Recent results indicate that hemocyanins can also function as phenoloxidases and here we show for the first time that hemocyanin can be converted to phenoloxidase. Furthermore, its substrate specificity can be switched between catecholoxidase and tyrosinase activity depending on effectors such as hydroxymethyl-aminomethan (Tris) and Mg2+-ions. Thi…
ADHD and DAT1: Further evidence of paternal over-transmission of risk alleles and haplotype
2010
Contains fulltext : 87259.pdf (Publisher’s version ) (Closed access) We [Hawi et al. (2005); Am J Hum Genet 77:958-965] reported paternal over-transmission of risk alleles in some ADHD-associated genes. This was particularly clear in the case of the DAT1 3'-UTR VNTR. In the current investigation, we analyzed three new sample comprising of 1,248 ADHD nuclear families to examine the allelic over-transmission of DAT1 in ADHD. The IMAGE sample, the largest of the three-replication samples, provides strong support for a parent of origin effect for allele 6 and the 10 repeat allele (intron 8 and 3'-UTR VNTR, respectively) of DAT1. In addition, a similar pattern of over-transmission of paternal ri…
Physiology and Pathology of Ovarian Hyperstimulation Syndrome
2010
Ovarian hyperstimulation syndrome (OHSS) occurs when ovaries primed with follicle-stimulating hormone/leuteinizing hormone (LH) are subsequently exposed to human chorionic gonadotropin (hCG). The ultimate pathophysiological step underlying this clinical picture is increased vascular permeability (VP). With the administration of hCG, the expression vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR-2) mRNA increases significantly rising to a maximum coinciding with peaked VP. Immunohistochemistry shows the presence of VEGF and VEGFR-2 proteins in the granulosa-lutein and endothelial cells of the entire corpus luteum. These findings suggest that the syndrome can be prevented…
Dopamine agonist administration causes a reduction in endometrial implants through modulation of angiogenesis in experimentally induced endometriosis
2009
Survival of newly implanted retrograde-shed endometrial tissue during menstruation in an ectopic location requires an adequate blood supply. This suggests that angiogenesis is a prerequisite for the development of endometriosis and that its inhibition may be a target for preventing development. Previous studies have shown that vascular endothelial growth factor (VEGF), a heparin-binding glycoprotein, has an essential role in angiogenesis. The main regulatory factor for angiogenesis appears to be binding of VEGF to its type-2 receptor (VEGFR-2). Cabergoline (Cb2) and other dopamine agonists promote endocytosis of the VEGF receptor-2 (VEGFR-2) in endothelial cells, thereby preventing VEGF-VEG…
Dopamine Use in Intensive Care: Are We Ready to Turn it Down?
2013
Dopamine is still frequently used as a first line vasopressor agent in hypotensive patients, when physicians are afraid of noradrenaline and believe that dopamine, with its β and α, inotrope and vasopressor effects, may be helpful. Evidence exists that it does not offer protection from renal failure, even if at low doses (0, 3-5 mcg/Kg/min) it may exert its effects on D1 and D2 receptors resulting in natriuresis and renal vasodilation, augmentation in renal blood flow, and diuresis. The effects of dopamine on gastrointestinal system and splanchnic perfusion in critical care patients are even more controversial, since they seem to be at least partially dependent on the initial fractional spl…
Near-infrared light-responsive and antibacterial injectable hydrogels with antioxidant activity based on a Dopamine-functionalized Gellan Gum for wou…
2022
The development of wound dressings with combined antioxidant, antibacterial and tissue adhesion functions has been a difficult medical task for the treatment of wound infections. We synthetized a dopamine and PEG functionalized Gellan Gum (GG) to produce an injectable hydrogel with radical scavenging activity having both specific and aspecific antibiotic/antimicrobial properties. Using starting GG with different molecular weights, we obtained two derivatives that have been used to prepare the gel precursor dispersion, that undergoes gelation in the presence of colistin and dried microparticles (MPs) functionalized on the surface with polydopamine (pDA). Both were used to dope the hydrogel, …
Microglia and α-synuclein implication in Parkinson's disease
2011
Age-related neurodegenerative disorders like Parkinson’s disease take an enormous toll on individuals and on society. Despite extensive efforts, Parkinson’s disease remains incurable and only very limited treatments exist. Indeed, Parkinson’s pathogenesis is still not clear and research on its molecular mechanisms is ongoing. In this study, we focused our interest on two abnormal events occurring in Parkinson’s patients, namely α-synuclein aggregation and microglial activation. We first investigated α-synuclein and its abnormal polymerisation. For this purpose, we developed novel methods, which allowed the in vitro production of different types of α-synuclein oligomers. Using highly sensiti…