Browsing by Subject "Dopamine"

Now showing 1 - 6 of 6
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    Comparative Analysis of Tyrosine Hydroxylase Amacrine Cells in the Mammalian Retina: Distribution and Quantification in Mouse, Rat, Ground Squirrel and Macaque Retinas
    (MDPI, 2025-07-20) Kiyoharu J. Miyagishima; Xiaomin Lai; Amurta Nath; William N. Grimes; Xiyuan Ping; Jeffrey S. Diamond; Morven A. Cameron; Wei Li; Francisco M. Nadal-Nicolás; Francisco M. Nadal-Nicolás; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Francisco M. Nadal-Nicolás; Facultades de la UMU::Facultad de Medicina
    Dopaminergic amacrine cells (DACs) are a subclass of amacrine cells that modulate retinal processing and light adaptation by releasing dopamine. Although the role of dopamine is largely conserved, their retinal distribution across mammals remains incompletely characterized. In mice, rats, thirteen-lined ground squirrels (TLGSs), and macaques, we systematically compared the localization, number, and topography of DACs by their expression of tyrosine hydroxylase (TH), a crucial enzyme in the biosynthesis of dopamine. In all species examined, TH+ cells were primarily located in the inner nuclear layer; however, there was a species-dependent influence on their number and distribution. Mice exhibited the highest density of TH+cells but completely lacked displaced TH+cells (dTH+cells) in the ganglion cell layer. Despite interspecies variation in the total number of TH+cells in the retina, the overall density in rats, TLGSs, and macaques was similar. Most species displayed a higher density of DACs toward central retinal regions. However, rats exhibited a distinctive dorsal concentration, particularly among dTH+cells. Although most species examined exhibited a similar ratio of TH+cells to Brn3a+ retinal ganglion cells, TLGSs showed a marked reduction, indicating a potentially diminished dopaminergic modulatory role. Species-specific DAC topographies aligned with specialized visual regions, such as the visual streak in TLGS and the macula in macaques. These results reveal both conserved and divergent features of retinal dopamine circuitry, reflecting evolutionary adaptations to visual processing demands.
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    Dysregulation of dopaminergic regulatory mechanisms in the mesolimbic pathway induced by morphine and morphine withdrawal
    (Springer, 2015) López Bellido, Roger; Rodríguez, Raquel E.; Núñez Parra, Cristina; García Pérez, Daniel; Laorden Carrasco, María Luisa; Milanés Maquilón, María Victoria; Farmacología; Facultades de la UMU::Facultad de Medicina
    Dopamine (DA) is thought to represent a teaching signal and has been implicated in the induction of addictive behaviours. Previously, it has been proposed that the transcription factors Nurr1 and Pitx3, which are critical for transcription of a set of genes involved in DA metabolism in the mesolimbic pathway, are associated with addiction pathology. The aim of our study was to investigate abnormalities in the mesolimbic pathway associated with morphine dependence and withdrawal. Using quantitative real-time PCR, immunofluorescence, HPLC and Western blotting, here we studied the effects of single morphine administration, morphine dependence and morphine withdrawal on Nurr1 and Pitx3 expression as well as on the DA marker tyrosine hydroxylase (TH) and the turnover of DA in the ventral tegmental area (VTA) and/or nucleus accumbens. We showed that the three experimental conditions caused induction of Nurr1 and Pitx3 in the VTA, which correlated with changes in TH expression during chronic morphine administration. Present data also confirmed the colocalization of Nurr1 and Pitx3 with TH-positive neurons in the posterior VTA. Furthermore, during morphine dependence, Nurr1 was detected in the nucleus compartment of VTA TH-positive neurons, whereas Pitx3 was strongly detected in the nucleus of TH-positive neurons after single morphine administration and during morphine withdrawal. The number of TH neurons, number of Nurr1 or Pitx3-positive cells, and the number of TH neurons expressing Nurr1 or Pitx3 were not modified in the subpopulations of DA neurons. Present data provide novel insight into the potential correlation between Nurr1 and Pitx3 and DA neurons plasticity during opiate addiction in the mesolimbic pathway.
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    Formation of carboxylated and decarboxylated betalains in ripening grains of Chenopodium quinoa by a dual dioxygenase
    (Oxford University Press, Society for Experimental Biology, 2022-04-07) Henarejos Escudero, Paula; Martínez-Rodríguez, Pedro; Gomez-Pando, Luz Rayda; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular "A"
    Chenopodium quinoa (quinoa) is a pseudo-cereal that forms part of the cultural heritage of Andean countries, and its grains have high nutritional value and potential health benefits. Betalains are nitrogenous water-soluble pigments and bioactive molecules that contribute to these health-promoting properties. Betalains are restricted to plants of the order Caryophyllales, to which quinoa belongs. A new family of betalains has been discovered in the form of unconventional decarboxylated pigments. Here, we show that these pigments accumulate in ripening quinoa grains of fluorescent nature, and are putatively based on a dopamine-cleaving activity. This study describes for the first time the purification and molecular and functional characterization of a 4,5-dopamine extradiol dioxygenase enzyme from plants. It is a monomeric protein with a molecular mass of 34.5 kDa characterized by chromatography, electrophoresis, and time-offlight mass spectrometry. We demonstrate that this key enzyme has a dual function in a square-shaped biosynthetic pathway towards the formation of both carboxylated and decarboxylated pigments. Enzyme kinetic properties are characterized for the production of 6-decarboxy-betalamic acid and 3,4-dihydroxy-l-phenylalanine-derived betalamic acid, the two structural units of plant pigment in nature. The profile of multiple betalains present in quinoa grains has been reproduced in one-pot bioreactors containing the novel enzyme and two competing substrates
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    Parkinson's disease: a short story of 200 years
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Cuenca, L.; Cano Fernandez, L.; Sanchez Rodrigo, C.; Estrada, C.; Fernández Villalba, Emiliano; Herrero Ezquerro, María Trinidad; Gil Martínez, Ana Luisa
    After Alzheimer’s disease, Parkinson’s disease (PD) is the second most prevalent and incidental neurodegenerative disorder, affecting more than 2% of the population older than 65 years old. Since it was first described 200 years ago by Dr James Parkinson, great steps have been made in the understanding of the pathology. However, the cause(s) that initiates and perpetuates the neurodegenerative process is (are) still not clear. Thus, early diagnosis is not available, nor are there efficient therapies that can stop neurodegeneration. PD clinical features are defined by motor (like bradykinesia, resting tremor, gait impairment) and nonmotor symptoms (like constipation, apathy, fathigue, olfactory dysfunction, depression and cognitive decline) that get more severe as the disease advances. Neuropathological hallmarks comprise selective loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc) and Lewy bodies (LB) in different nuclei of the nervous system. Numerous studies have shown that these pathological features are aggravated by the confluence of other contributing factors, such as a genetic component, exposure to environmental toxins, mitochondrial dysfunction, increase of oxidative stress, calcium imbalance and chronic neuroinflammation, among others. Here, we provide a summary of the actual state of PD’s pathology, the most studied molecular mechanisms, classic and novel therapeutic strategies and diagnosis methods, especially highlighting recent advances in these 200 years
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    Production of dihydroxylated betalains and dopamine in cell suspension cultures of Celosia argentea var. plumosa
    (American Chemical Society, 2015-03-01) Guadarrama-Flores, Berenice; Rodríguez-Monroy, Mario; Cruz-Sosa, Francisco; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular "A"
    Betalains are plant pigments of hydrophilic nature with demonstrated chemopreventive potential in cancer celllines and animal models. Among the betalains, those containing an aromatic moiety with two free hydroxyl groups possess thestrongest antioxidant and free radical scavenging activities. The betaxanthins dopaxanthin and miraxanthin V and the betacyaninsbetanidin and decarboxy-betanidin are the only natural betalains with catecholic substructures. These four pigments have beenproduced in cell cultures established from hypocotyls of the plant Celosia argentea. Two stable and differentially colored cell lines,yellow and red, were maintained on Murashige and Skoog medium supplemented with the plant growth regulators 6-benzylaminopurine (6.66 μM) and 2,4-dichlorophenoxyacetic acid (6.79 μM). Derived suspension cultures showed increasedproduction of dihydroxylated betalains in the cells and secreted to the medium with a maximum reached after 8 days of culture.In addition, precursor molecules betalamic acid and dopamine, with content up to 42.08 mg/g dry weight, were also obtained.The joint presence of the bioactive betalains together with the production of dopamine and betalamic acid show the ability of cellcultures of C. argentea to become a stable source of valuable phytochemicals
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    Sympathetic nervous system contributes to orthodontic tooth movement by central neural regulation from hypothalamus
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Cao, Haifeng; Fang, Bing; Wang, Xudong; Zhou, Yanheng
    Orthodontic tooth movement (OTM) is a specific treatment of malocclusion, whose regulation mechanism is still not clear. This study aimed to reveal the relationship between the sympathetic nervous system (SNS) and OTM through the construction of an OTM rat model through the utilization of orthodontic nickeltitanium coiled springs. The results indicated that the stimulation of SNS by dopamine significantly promote the OTM process represented by the much larger distance between the first and second molar compared with mere exertion of orthodontic force. Superior cervical ganglionectomy (SCGx) can alleviate this promotion effect, further proving the role of SNS in the process of OTM. Subsequently, the ability of orthodontic force to stimulate the center of the SNS was visualized by the tyrosin hydroxylase (TH) staining of neurons in ventromedial hypothalamic nucleus (VMH) and arcuate nucleus (ARC) of the hypothalamus, as well as the up-regulated expression of norepinephrine in local alveolar bone. Moreover, we also elucidated that the stimulation of SNS can promote osteoclast differentiation in periodontal ligament cells (PDLCs) and bone marrow-derived cells (BMCs) through regulation of receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) system, thus promoting the OTM process. In conclusion, this study provided the first evidence for the involvement of the hypothalamus in the promotion effect of SNS on OTM. This work could provide a novel theoretical and experimental basis for further understanding of the molecular mechanism of OTM.