Search results for " plastic"
showing 10 items of 3463 documents
Endocannabinoid Role in Synaptic Plasticity and Learning
2009
Endocannabinoids have recently emerged as versatile modulators of synaptic transmission and can act as retrograde neurotransmitters. As they cannot be stored in synaptic vesicles, endocannabinoid signaling is believed to start ‘on-demand,’ via a stimulus-dependent synthesis from membranous precursors at the postsynaptic site. After synthesis, endocannabinoids bind presynaptically to cannabinoid type 1 (CB1) receptors, leading to a short- or long-term suppression of neurotransmitter release. CB1 receptors are present in a plethora of different synaptic connections in the brain. Electrophysiological and behavioral analyses of mutant mice lacking CB1 receptors and of pharmacologically treated …
Hyaluronan‐coated poly(propylene imine) dendrimers as biomimetic nanocarriers of doxorubicin
2022
A coating technology based on low molecular weight hyaluronic acid (HA) and ferulic acid (FA) was applied to the coating of low generation poly(propylene imine) dendrimers through a biocompatible hexa(ethylene glycol) spacer. The ensuing HA-FA-HEG-PPID dendrimeric materials showed interesting loading capability (between 7.65% and 9.08%) regarding anticancer agent doxorubicin, and their interactions with the drug appeared to hamper the drug release in the physiological environment. Thus, the stable nanostructured loaded delivery systems were able to internalize into cells expressing the HA receptor CD44 and to demonstrate high cytotoxicity comparable to that shown by equivalent amounts of fr…
Perorāli ievadīta metformīna ietekme uz neiroiekaisumu un smadzeņu neironālo plasticitāti Alcheimera slimības tipa modeļa žurkās
2019
Alcheimera slimība (AD) ir pasaulē visbiežāk sastopamā neirodeģeneratīvā saslimšana, kā arī biežākais demences izraisītājs, turklāt šīs slimības izplatība ar katru gadu pieaug. Līdz šim izmantota simptomātiska terapija un kopš 2003. gada nav apstiprināts neviens jauns medikaments AD ārstēšanai, tādēļ arvien tiek meklēti jauni terapijas virzieni (Hung and Fu, 2017). Ņemot vērā, ka AD pacientu smadzenēs novērojami glikozes metabolisma traucējumi un paaugstināts cerebrālais glikozes līmenis (Campbell et al., 2017), mēs pārbaudījām antidiabētiskā preparāta metformīna devu (75 mg/kg un 100 mg/kg) ietekmi uz neiroieksumu un neironālo plasticitāti streptozocīna (STZ) izraisītāAD tipa modeļa žurkās…
Blends of Semiflexible Polymers: Interplay of Nematic Order and Phase Separation
2021
Mixtures of semiflexible polymers with a mismatch in either their persistence lengths or their contour lengths are studied by Density Functional Theory and Molecular Dynamics simulation. Considering lyotropic solutions under good solvent conditions, the mole fraction and pressure is systematically varied for several cases of bending stiffness κ (the normalized persistence length) and chain length N. For binary mixtures with different chain length (i.e., NA=16, NB=32 or 64) but the same stiffness, isotropic-nematic phase coexistence is studied. For mixtures with the same chain length (N=32) and large stiffness disparity (κB/κA=4.9 to 8), both isotropic-nematic and nematic-nematic unmixing oc…
Ultrasound in peripheral nerve injuries: the challenge. Response
2017
Continuous neuronal integration in the cerebral cortex of rodents and humans
2021
La plasticidad neuronal es la capacidad del sistema nervioso para realizar cambios funcionales adaptativos, durante el desarrollo y la edad adulta. Se refiere a todo tipo de cambios que modifican la forma y estructura de las neuronas y de las células gliales del sistema nervioso central (SNC). Entre los diferentes niveles de plasticidad que ocurren en el cerebro adulto, la neurogénesis es un tipo de plasticidad cerebral, que implica la producción e incorporación continua de nuevas neuronas en las redes neuronales funcionales. En el cerebro de los mamíferos adultos, las nuevas neuronas se generan tradicionalmente en dos "nichos neurogénicos canónicos": la zona subventricular (SVZ) y la zona …
Nicotinic receptor agonists as neuroprotective/neurotrophic drugs. Progress in molecular mechanisms
2007
In the present work we reviewed recent advances concerning neuroprotective/neurotrophic effects of acute or chronic nicotine exposure, and the signalling pathways mediating these effects, including mechanisms implicated in nicotine addiction and nAChR desensitization. Experimental and clinical data largely indicate long-lasting effects of nicotine and nicotinic agonists that imply a neuroprotective/neurotrophic role of nAChR activation, involving mainly alpha 7 and alpha 4 beta 2 nAChR subtypes, as evidenced using selective nAChR agonists. Compounds interacting with neuronal nAChRs have the potential to be neuroprotective and treatment with nAChR agonists elicits long-lasting neurotrophic e…
Analysis of structural plasticity in the adult and adolescent mouse brain. Effects of erythropoietin
2019
INTRODUCCIÓN Los organismos están sujetos diariamente a cambios que ocurren en su entorno y dentro del propio organismo. Estas entradas de información del medio externo e interno son integradas y analizadas por el organismo con el fin de dar una respuesta adecuada que asegure la supervivencia. Es crucial, por lo tanto, que el sistema responda de forma apropiada al amplio abanico de cambios y demandas que acontecen a lo largo de la vida del organismo. En este aspecto, el sistema nervioso se destaca como uno de los principales sistemas encargados de mantener el orden interno y reaccionar con cambios adaptativos a los eventos que lo rodean. Un funcionamiento aberrante del sistema da lugar a la…
Impact of pharmacological and environmental manipulations on neuronal structural plasticity and dynamics
2017
El sistema nervioso de vertebrados es uno de los más estudiados, aunque peor comprendidos, del organismo de mamíferos. Desde que Ramón y Cajal postuló su teoría celular de este sistema (Ramón y Cajal 1909), la neurona se ha postulado como su unidad funcional. Sin embargo, durante las últimas décadas se ha revolucionado la visión que se tenía de éste. Una de las percepciones más asentadas era que, tras el desarrollo embrionario, el sistema nervioso se mantenía inmutable. Sin embargo, ahora sabemos que diferentes formas de plasticidad gobiernan su adaptación, que son necesarias para importantes procesos del día a día, tales como el aprendizaje y la memoria (Smythies 2002; Berlucchi and Buchte…
Modulation of Human Motor Cortical Excitability and Plasticity by Opuntia Ficus Indica Fruit Consumption: Evidence from a Preliminary Study through N…
2022
Indicaxanthin (IX) from Opuntia Ficus Indica (OFI) has been shown to exert numerous biological effects both in vitro and in vivo, such as antioxidant, anti-inflammatory, neuro-modulatory activity in rodent models. Our goal was to investigate the eventual neuro-active role of orally assumed fruits containing high levels of IX at nutritionally-relevant amounts in healthy subjects, exploring cortical excitability and plasticity in the human motor cortex (M1). To this purpose, we applied paired-pulse transcranial magnetic stimulation and anodal transcranial direct current stimulation (a-tDCS) in basal conditions and followed the consumption of yellow cactus pear fruits containing IX or white ca…