Glial Function in Homeostasis of the Neuronal Microenvironment

Physiology ◽  
1994 ◽  
Vol 9 (6) ◽  
pp. 265-267
Author(s):  
RK Orkand ◽  
SC Opava

Neuroglia buffer changes in the concentrations of ions and small molecules in the tortuous network of narrow extracellular clefts that constitutes the functional environment of neurons in the central nervous system. The large area of glial membrane bordering this space exhibits specific membrane transport systems for homeostasis.

Author(s):  
S Dingezweni

The blood–brain barrier (BBB) is a dynamic barrier essential for central nervous system interstitial fluid separation from circulating blood. This dynamic separation ensures maintenance of neuronal microenvironment homeostasis against that of the everchanging in solutes and toxin concentration in circulating blood. The blood–brain barrier structure is complex, it has multiple contributors, such as specialised blood microvascular endothelium, neurons, astrocytes and pericytes. Transfer of essential nutrients to the brain and waste products from the brain to circulating blood is tightly regulated and facilitated by a large surface area and specialised transport systems. It is not only the physical characteristics of the barrier that assist in maintenance of neuronal microenvironment, biochemical substances and the high trans endothelial electrical resistance also play a major role. Circumventricular organs are those parts of the central nervous system lacking the blood–brain barrier. These are essential for optimum central nervous system interaction with circulating blood directly or using neurotransmitters. Primary or secondary central nervous system pathological states, such as infective and noninfective causes, directly or indirectly induce biochemical mediators that may disrupt and alter blood–brain barrier structure and function. Understanding of the blood–brain barrier anatomy and physiology assists in developing treatment methods to overcome degenerative and pathological states negatively affecting the central nervous system.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1236
Author(s):  
Keisuke Tachibana ◽  
Yumi Iwashita ◽  
Erika Wakayama ◽  
Itsuki Nishino ◽  
Taiki Nishikaji ◽  
...  

The blood-brain barrier (BBB), which is composed of endothelial cells, pericytes, astrocytes, and neurons, separates the brain extracellular fluid from the circulating blood, and maintains the homeostasis of the central nervous system (CNS). The BBB endothelial cells have well-developed tight junctions (TJs) and express specific polarized transport systems to tightly control the paracellular movements of solutes, ions, and water. There are two types of TJs: bicellular TJs (bTJs), which is a structure at the contact of two cells, and tricellular TJs (tTJs), which is a structure at the contact of three cells. Claudin-5 and angulin-1 are important components of bTJs and tTJs in the brain, respectively. Here, we review TJ-modulating bioprobes that enable drug delivery to the brain across the BBB, focusing on claudin-5 and angulin-1.


RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8505-8515
Author(s):  
Qinghua Wang ◽  
Shang Cheng ◽  
Fen Qin ◽  
Ailing Fu ◽  
Chen Fu

Rabies virus glycoprotein (RVG) peptides have been developed to deliver drugs for CNS diseases. In the present review, RVG-mediated drug delivery systems are summarised, which can deliver almost all small molecules and macromolecule agents.


In a previous paper it was shown that the method of local strychnization of the central nervous system not only yields good results in investigations on the sensory mechanisms of the spinal cord, but also with regard to the problem of the localization of the sensory area (sensibility) in the cerebral cortex. The writer then showed that there exists on the convexity of the cortex of the cat a large area, intimately connected with sensory functions. The slight strychnization of a very small part of this so-called “active zone” gives rise to intense symptoms of sensory excitation, whereas the application of the strychnine to parts of the cortex outside this area is not followed by like disturbances. The sensory disturbances produced by the poisoning of that part of the cerebral cortex affect both cutaneous and deep sensibility. They manifest themselves in the cat so far as the skin is concerned by:—


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