- MeSH
- buněčná a tkáňová terapie * MeSH
- Publikační typ
- biografie MeSH
- O autorovi
- Jendelová, Pavla, 1965- Autorita
Volume transmission is a form of intercellular communication that does not require synapses; it is based on the diffusion of neuroactive substances across the brain extracellular space (ECS) and their binding to extrasynaptic high-affinity receptors on neurons or glia. Extracellular diffusion is restricted by the limited volume of the ECS, which is described by the ECS volume fraction α, and the presence of diffusion barriers, reflected by tortuosity λ, that are created, for example, by fine astrocytic processes or extracellular matrix (ECM) molecules. Organized astrocytic processes, ECM scaffolds or myelin sheets channel the extracellular diffusion so that it is facilitated in a certain direction, i.e. anisotropic. The diffusion properties of the ECS are profoundly influenced by various processes such as the swelling and morphological rebuilding of astrocytes during either transient or persisting physiological or pathological states, or the remodelling of the ECM in tumorous or epileptogenic tissue, during Alzheimer's disease, after enzymatic treatment or in transgenic animals. The changing diffusion properties of the ECM influence neuron-glia interaction, learning abilities, the extent of neuronal damage and even cell migration. From a clinical point of view, diffusion parameter changes occurring during pathological states could be important for diagnosis, drug delivery and treatment.
- MeSH
- anizotropie MeSH
- astrocyty patologie MeSH
- difuze MeSH
- extracelulární matrix fyziologie MeSH
- lidé MeSH
- mezibuněčná komunikace fyziologie MeSH
- nervový přenos fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Most hypotheses concerning the mechanisms underlying seizure activity in focal cortical dysplasia (FCD) are based on alterations in synaptic transmission and glial dysfunction. However, neurons may also communicate by extrasynaptic transmission, which was recently found to affect epileptiform activity under experimental conditions and which is mediated by the diffusion of neuroactive substances in the extracellular space (ECS). The ECS diffusion parameters were therefore determined using the real-time iontophoretic method in human neocortical tissue samples obtained from surgically treated epileptic patients. The obtained values of the extracellular space volume fraction and tortuosity were then correlated with the histologicaly assessed type of cortical malformation (FCD type I or II). While the extracellular volume remained unchanged (FCD I) or larger (FCD II) than in normal/control tissue, tortuosity was significantly increased in both types of dysplasia, indicating the presence of additional diffusion barriers and compromised diffusion, which might be another factor contributing to the epileptogenicity of FCD.
- MeSH
- dítě MeSH
- dospělí MeSH
- epilepsie patologie MeSH
- extracelulární prostor fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- malformace mozkové kůry patologie MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mozková kůra abnormality patologie MeSH
- neurony patologie fyziologie MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The diffusion of neuroactive substances in the extracellular space (ECS) plays an important role in short- and long-distance communication between nerve cells and is the underlying mechanism of extrasynaptic (volume) transmission. The diffusion properties of the ECS are described by three parameters: 1. ECS volume fraction alpha (alpha=ECS volume/total tissue volume), 2. tortuosity lambda (lambda2=free/apparent diffusion coefficient), reflecting the presence of diffusion barriers represented by, e.g., fine neuronal and glial processes or extracellular matrix molecules and 3. nonspecific uptake k'. These diffusion parameters differ in various brain regions, and diffusion in the CNS is therefore inhomogeneous. Moreover, diffusion barriers may channel the migration of molecules in the ECS, so that diffusion is facilitated in a certain direction, i.e. diffusion in certain brain regions is anisotropic. Changes in the diffusion parameters have been found in many physiological and pathological states in which cell swelling, glial remodeling and extracellular matrix changes are key factors influencing diffusion. Changes in ECS volume, tortuosity and anisotropy significantly affect the accumulation and diffusion of neuroactive substances in the CNS and thus extrasynaptic transmission, neuron-glia communication, transmitter "spillover" and synaptic cross-talk as well as cell migration, drug delivery and treatment.
- MeSH
- anizotropie MeSH
- centrální nervový systém fyziologie MeSH
- difuze MeSH
- extracelulární prostor fyziologie MeSH
- krysa rodu rattus MeSH
- lékové transportní systémy MeSH
- lidé MeSH
- myši transgenní MeSH
- myši MeSH
- neuroglie fyziologie MeSH
- neurony fyziologie MeSH
- pohyb buněk fyziologie MeSH
- signální transdukce fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- MeSH
- extracelulární prostor metabolismus MeSH
- gliom metabolismus patologie MeSH
- iontoforéza metody využití MeSH
- lidé MeSH
- mladiství MeSH
- Check Tag
- lidé MeSH
- mladiství MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- draslík fyziologie MeSH
- extracelulární prostor metabolismus MeSH
- fyziologický stres metabolismus MeSH
- krysa rodu rattus MeSH
- membránové potenciály fyziologie MeSH
- mícha MeSH
- neuroglie metabolismus MeSH
- osmotický tlak MeSH
- techniky in vitro MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- MeSH
- agonisté excitačních aminokyselin farmakologie MeSH
- krysa rodu rattus MeSH
- kyselina alfa-amino-3-hydroxy-5-methyl-4-isoxazolpropionová farmakologie MeSH
- kyselina glutamová farmakologie MeSH
- mícha patologie účinky léků MeSH
- N-methylaspartát farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
