Introduction: Epilepsy
Candace M. Kent, David M. Chan in Analysis of a Model for Epilepsy, 2022
Glia are specialized cells in the brain that make up part of the supportive tissue surrounding neurons and that include such cells as astrocytes and oligodendrocytes. Neurons are interconnected and communicate with each other through special junctions called synapses. A synapse is made up of a presynaptic element on the neuron sending the signal, a postsynaptic element on the neuron receiving the signal, and a gap junction between the two elements [42]. The term ictal is used when describing seizures, and the term interictal is used when describing the interim period between seizures. Epileptiform discharges are what are seen on electroencephalograms (EEGs) of epileptic individuals, but also of individuals without epilepsy but with a propensity toward having seizures.
Propagation of the Action Potential
Nassir H. Sabah in Neuromuscular Fundamentals, 2020
The solution, in the form of myelinated axons, is ingeniously simple and highly effective. The axon is surrounded by a myelin sheath consisting of up to 200 layers or so of passive cell membrane interrupted at regular intervals in what are referred to as the nodes of Ranvier (Figure 4.7). The region between adjacent nodes is the internode, whose length is roughly 100–150 times the axon diameter and ranges in length between about 200 µm and 2.5 mm, depending on axon diameter. The sheath is wrapped around the axon during embryonic development by specialized satellite cells of the nervous system – the glial cells (Section 1.2.3). In the central nervous system, the glial cells that form the myelin sheath are referred to as oligodendrocytes, with each oligodendrocyte forming one internode of myelin for up to about 50 adjacent axons. In the peripheral nervous system, a glial cell referred to as a Schwann cell forms one internode of only a single axon.
Biological Basis of Behavior
Mohamed Ahmed Abd El-Hay in Understanding Psychology for Medicine and Nursing, 2019
Nervous tissue is composed of two types of cells: neurons and glial cells. Neurons are the primary type of cells whose function is to receive and transmit information. They are responsible for the computation and communication that the nervous system provides. Glial cells or glia play a supporting role for nervous tissue. Neurons are composed of: (1) a cell body that contains the nucleus and most of the cell’s biosynthetic machinery and keeps the cell alive; (2) branching tree-like fibers called dendrites, which extend from the cell body, collect information from other cells and send the information to the cell body; (3) an axon, which transmits information away from the cell body to other neurons or to the muscles and glands; and (4) specialized regions, at the end of axons, called synaptic buttons or synaptic endings, where communication with other nerve cells or special effector tissues (such as gland or muscle cells) is carried out (Figure 5.2).
Dexmedetomidine postconditioning alleviates spinal cord ischemia-reperfusion injury in rats via inhibiting neutrophil infiltration, microglia activation, reactive gliosis and CXCL13/CXCR5 axis activation
Published in International Journal of Neuroscience, 2023
Fengshou Chen, Dan Wang, Yanhua Jiang, Hong Ma, Xiaoqian Li, He Wang
Astrocytes play an important role in the mechanism of delayed onset motor dysfunction in spinal cord I/R injury as one kind of Inflammatory cells [52]. After CNS ischemia, reactive astrocytes released inflammatory cytokines, free radicals, and glutamate, resulting in nerve cell injury [19,54]. Reactive astrocytes were important in regulating neuronal cell death after CNS ischemia [19,55]. The response of the adult mammalian CNS to injury resulted in a gliosis in the lesion and the formation of a glial scar [56]. Glial scar resulted in a physical and biochemical barrier of axon regeneration, and thus affected neurologic functional recovery after CNS injury [57,58]. Attenuation of reactive astrocytes promoted function recovery after spinal cord [59,60]. In our study, we found that GFAP immunoreactivity was significantly elevated at 24 h after spinal cord I/R injury. And the increase of GFAP immunoreactivity was reduced by DEX postconditioning, which was consistent with the treatment effects of DEX in an experimental model of fibromyalgia [20]. The neuroprotective effects might be due to the reduction of inflammatory cytokines release via attenuation of reactive astrocytes. The medium DEX postconditioning significantly reduced GFAP immunoreactivity than other two doses of DEX postconditioning.
Cyanidin inhibits glioma stem cells proliferation through the Wnt signaling pathway
Published in International Journal of Neuroscience, 2022
Zicheng Xue, Lei Tian, Hui Zheng, Yucai Zhang, Junying Song
Glioma occurs in glial supporting cells (glial cells), which surround nerve cells and help them perform functional roles. There are currently three types of glial cells that can produce tumors. The survival period of glioma patients is closely related to the patient’s pathological grade, treatment strategy, and molecular profile. The responses of different cell lines may reflect the characteristics of different molecular types of gliomas. Glioma is classified and treated according to the similarity between its tumor cell morphology and normal brain glial cells (not necessarily its true cell origin). Targeting glioma tumor stem cells will be helpful for the treatment. Resveratrol was reported to inhibit the proliferation and movement of glioma stem cells through the Wnt pathway [11]. Cyanidin and Resveratrol belong to the same class of natural polyphenols, the most potent SIRT6 activator [12], so it is reasonable to speculate that their actions are similar. In this study, the cell lines used are known to have stem cell characteristics, and an inhibition effect of cyanidin was suggested, which is also the novelty of this study.
Characterization of a novel stimulus-induced glial calcium wave in Drosophila larval peripheral segmental nerves and its role in PKG-modulated thermoprotection
Published in Journal of Neurogenetics, 2021
Jennifer L. Krill, Ken Dawson-Scully
Mitochondrial Ca2+ signaling plays an important role in a cell’s decision to activate cell death pathways or continue function under non-physiological conditions (Kalimuthu & Se-Kwon, 2013; Niemi & MacKeigan, 2013). Glia serve an important role in the maintenance of neuronal function by providing neurons with the oxygen and nutrients required for cell processes (Araque & Navarrete, 2010). Glia are also responsible for regulating neuronal activity (Seifert, Schilling, & Steinhäuser, 2006; Tzingounis & Wadiche, 2007) and these cells are equipped with sensors that enable them to monitor and process information regarding neuronal signaling (Perea & Araque, 2005). In the presence of abnormal neuronal activity, glial cells can alter extracellular ionic environments to excite or curb the activity of neurons (Seifert et al., 2006; Tzingounis & Wadiche, 2007). Because the glial wave characterized in these experiments is only observed during non-physiological conditions, this could be a homeostatic signaling mechanism.