Astrocytes can be defined as the glia inhabiting the nervous system with the main function in the maintenance of nervous tissue homeostasis. Classified into several types according to their morphological appearance, many of astrocytes form a reticular structure known as astroglial syncytium, owing to their coupling via intercellular channels organized into gap junctions. Not only do astrocytes establish such homocellular contacts, but they also engage in intimate heterocellular interactions with neurons, most notably at synaptic sites. As synaptic structures house the very core of information transfer and processing in the nervous system, astroglial perisynaptic positioning assures that these glial cells can nourish neurons and establish bidirectional communication with them, functions outlined in the concepts of the astrocytic cradle and multi-partite synapse, respectively. Astrocytes possess a rich assortment of ligand receptors, ion and water channels, and ion and ligand transporters, which collectively contribute to astrocytic control of homeostasis and excitability. Astroglia control glutamate and adenosine homeostasis to exert modulatory actions affecting the real-time operation of synapses. Fluctuations of intracellular calcium can lead to the release of various chemical transmitters from astrocytes through a process termed gliotransmission. Sodium fluctuations are closely associated to those of calcium with both dynamic events interfacing signaling and metabolism. Astrocytes appear fully integrated into the brain cellular circuitry, being an indispensable part of neural networks.
This book is the introduction to a series of e-books dedicated to the physiology and pathophysiology of neuroglia. The topic of neuroglia is generally overlooked in neuroscience curricula across the world, the main attention being focused on the description of excitability of neurons and neuronal networks. The neuroglia, being electrically non-excitable, are universally regarded as supportive cells which do not contribute to information processing. This oversimplified view, however, ignores the tremendous importance of brain homeostasis, which is imperative for the ongoing activity of neuronal networks. It also ignores the truth that specialization of neurons and their ability for rapid propagation and multi-level integration of signals become possible only because of delegation of homeostatic abilities to neuroglia. Furthermore, glial cells contribute to information processing as they can modulate neuronal synaptic transmission. Finally, neuroglia provide the only system of brain defense and as such these cells are intimately involved in all types of neuropathologies, and contribute to both neuroprotection and regeneration of the nervous system. The e-books in this series provide a platform for in-depth learning of all aspects of neuroglial cells function in health and disease.
The scientific and therapeutic implications of a new way of understanding a common disease. Depression has often been studied, but this multifaceted disease remains far from understood. Here, leading researchers present a major new view of the disorder that synthesizes multiple lines of scientific evidence from neurobiology, mindfulness, and genetics. A comprehensive mind-body approach to understanding, evaluating, and treating this disease.
Astrocytes were the original neuroglia that Ramón y Cajal visualized in 1913 using a gold sublimate stain. This stain targeted intermediate filaments that we now know consist mainly of glial fibrillary acidic protein, a protein used today as an astrocytic marker. Cajal described the morphological diversity of these cells with some ast- cytes surrounding neurons, while the others are intimately associated with vasculature. We start the book by discussing the heterogeneity of astrocytes using contemporary tools and by calling into question the assumption by classical neuroscience that neurons and glia are derived from distinct pools of progenitor cells. Astrocytes have long been neglected as active participants in intercellular communication and information processing in the central nervous system, in part due to their lack of electrical excitability. The follow up chapters review the “nuts and bolts” of ast- cytic physiology; astrocytes possess a diverse assortment of ion channels, neu- transmitter receptors, and transport mechanisms that enable the astrocytes to respond to many of the same signals that act on neurons. Since astrocytes can detect chemical transmitters that are released from neurons and can release their own extracellular signals there is an increasing awareness that they play physiological roles in regulating neuronal activity and synaptic transmission. In addition to these physiological roles, it is becoming increasingly recognized that astrocytes play critical roles during pathophysiological states of the nervous system; these states include gliomas, Alexander disease, and epilepsy to mention a few.
This text book will bring together a mix of both internationally known and established senior scientists along side up and coming (but already accomplished) junior scientists that have varying expertise in fundamental and applied nanotechnology to biology and medicine.
This will help us customize your experience to showcase the most relevant content to your age group
Please select from below
Login
Not registered?
Sign up
Already registered?
Success – Your message will goes here
We'd love to hear from you!
Thank you for visiting our website. Would you like to provide feedback on how we could improve your experience?
This site does not use any third party cookies with one exception — it uses cookies from Google to deliver its services and to analyze traffic.Learn More.