Natural Substances that Enhance the Integrity and Function of the Neuroglia (Glial cells)

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Neuroglia (Glial cells)

Glial cells, sometimes called neuroglia or simply glia, are non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the brain and peripheral nervous system.

 

Figure 1  Neuroglia cells of the CNS

There are four main functions of glial cells:

  • To surround neurons and hold them in place
  • To supply nutrients and oxygen to neurons
  • To insulate one neuron from another
  • To destroy pathogens and remove dead neurons

The Table below lists those natural substances that enhance the glial cells:

Substances that Enhance the Glial Cells

CategorySubstanceReference
Hormones
DHEA1
Nootropics
Deprenyl2
Polyphenols
Curcumin3
Vitamins
Vitamin C4

Types of Glia

There are generally 6 types of glial cells:

  • Macroglial Cells
    • Astrocyte
    • Oligodendroglia
  • Microglia Cells
  • Schwann Cells
  • Ependyma Cells
  • Satellite Cells

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Figure 2  Types of Neuroglia

Macroglia

Macroglia cells include astrocytes, oligodendrogliocytes and glioblasts; they provide nutrition, physical support and synthesise myelin.

There are two main types of Macroglia:

Astrocytes

Astrocytes (Astro from Greek astron = star and cyte from Greek “kyttaron” = cell), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They are the most abundant cells of the human brain. They perform many functions, including biochemical support of endothelial cells that form the blood–brain barrier, provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, and a role in the repair and scarring process of the brain and spinal cord following traumatic injuries.

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Figure 3 Astrocyte

They regulate the external chemical environment of neurons by removing excess ions, the notable one being potassium, and recycling neurotransmitters released during synaptic transmission. The current theory suggests that astrocytes may be the predominant “building-blocks” of the blood–brain barrier. Astrocytes may regulate vasoconstriction and vasodilation by producing substances such as arachidonic acid, whose metabolites are vasoactive.

Astrocytes signal each other using calcium. The gap junctions (also known as electrical synapses) between astrocytes allow the messenger molecule IP3 to diffuse from one astrocyte to another. IP3 activates calcium channels on cellular organelles, releasing calcium into the cytoplasm. This calcium may stimulate the production of more IP3. The net effect is a calcium wave that propagates from cell to cell. Extracellular release of ATP, and consequent activation of purinergic receptors on other astrocytes, may also mediate calcium waves in some cases.

It has recently been shown that astrocyte activity is linked to blood flow in the brain.

Astrocytes can actually communicate with neurons and modify the signals they send and receive. That means astrocytes are much more involved than once thought in both the processing of information, and the signaling at the synapse.

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Figure 4  Astrocytes communicate with neurons

The Table below lists those natural substances that enhance astrocytes:

Substances that Enhance the Astrocytes

CategorySubstanceReference
Herbs
Korean Ginseng1
Hormones
Melatonin2
Nootropics
Idebenone3
Piracetam4
Vinpocetine5
Organic Acids
Rosmarinic Acid6
Peptides
Carnosine7
Vitamins
Vitamin D8

Oligodendroglia

Oligodendrocytes are cells that coat axons in the central nervous system (CNS) with their cell membrane, forming a specialized membrane differentiation called myelin, producing the so-called myelin sheath. The myelin sheath provides insulation to the axon that allows electrical signals to propagate more efficiently.

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Figure 5 Oligodendrocyte

Their main functions of Oligodendroglia are to provide support and insulation to axons in the central nervous system of some vertebrates, equivalent to the function performed by Schwann cells in the peripheral nervous system. Oligodendrocytes do this by creating the myelin sheath, which is 80% lipid and 20% protein.

A single oligodendrocyte can extend its processes to 50 axons, wrapping approximately 1 μm of myelin sheath around each axon; Schwann cells, on the other hand, can wrap around only 1 axon. Each oligodendrocyte forms one segment of myelin for several adjacent axons.

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Figure 6  Oligodendrocyte wrapping mylein sheath around each axon

The Table below lists those natural substances that enhance the Oligodendroglia:

Substances that Enhance the Oligodendroglia

CategorySubstanceReference
Amino Acids
N-Acetyl-Cysteine (NAC)1
Lipids
Gamma-Linolenic Acid (GLA)2
Quinones
Coenzyme Q103
Vitamins
Vitamin K4

Microglia

Microglia are specialized macrophages capable of phagocytosis that protect neurons of the central nervous system.  Microglia act as the first and main form of active immune defense in the central nervous system (CNS).  They are derived from hematopoietic stem cells in mesodermal tissue; they are commonly categorized as such because of their supportive role to neurons.

These cells are found in all regions of the brain and spinal cord. Microglial cells are small relative to macroglial cells, with changing shapes and oblong nuclei. They are mobile within the brain and multiply when the brain is damaged. In the healthy central nervous system, microglia processes constantly sample all aspects of their environment (neurons, macroglia and blood vessels).

Microglia constitute 10-15% of all cells found within the brain.

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Figure 7  Microglia

The Table below lists those natural substances that enhance the Microglia:

Substances that Enhance the Microglia

Microglia  
CategorySubstanceReference
Nootropics
Nicergoline1
Vitamins
Vitamin D2

Schwann Cells

Schwann cells provide myelination to axons in the peripheral nervous system (PNS). They also have phagocytotic activity and clear cellular debris that allows for regrowth of PNS neurons.

There are two types of Schwann cell, myelinating and nonmyelinating. Myelinating Schwann cells wrap around axons of motor and sensory neurons to form the myelin sheath.

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Figure 8  Schwann cells

Schawann cells are involved in many important aspects of peripheral nerve biology—the conduction of nervous impulses along axons, nerve development and regeneration, trophic support for neurons, production of the nerve extracellular matrix, modulation of neuromuscular synaptic activity, and presentation of antigens to T-lymphocytes.

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Figure 9 Schwann cell nucleus

The Table below lists those natural substances that enhance Schwann cells:

Substances that Enhance the Schwann Cells

Schwann Cells  
CategorySubstanceReference
Alkaloid
Berberine1
Herbs
Ginko Biloba2
Korean Ginseng3
Lipids
Forskolin4
Minerals
Zinc5
Polyphenols
Quercetin6
Vitamins
Vitamin B127
Pyrroloquinoline Quinone8

Ependyma Cells

Ependyma is the thin epithelial-like lining of the ventricular system of the brain and the central canal of the spinal cord. Ependyma is one of the four types of neuroglia in the central nervous system (CNS). It is involved in the production of cerebrospinal fluid (CSF), and is shown to serve as a reservoir for neuroregeneration.

Satellite Cells

Satellite glial cells are glial cells that cover the surface of nerve cell bodies in sensory, sympathetic and parasympathetic ganglia.  Both satellite glial cells (SGCs) and Schwann cells (the cells that ensheath some nerve fibers) are derived from the neural crest of the embryo during development.  SGCs have been found to play a variety of roles, including control over the microenvironment of sympathetic ganglia.

The Table below is a summary of the natural substances and the various types of neuroglia:

Summary of Substances that Enhance the Function of the Neuroglia

CategorySubstanceGlialAstrocytesOligodendrogliaMicrogliaSchwann Cells#
Alkaloid
BerberineX1
Amino Acids
N-Acetyl-Cysteine (NAC)X1
Herbs
Korean GinsengXX2
Ginko BilobaX1
Hormones
MelatoninX1
DHEAX1
Lipids
GLAX1
ForskolinX1
Minerals
ZincX1
Nootropics
NicergolineX1
VinpocetineX1
DeprenylX1
PiracetamX1
IdebenoneX1
Peptides
CarnosineX1
Polyphenols
CurcuminX1
QuercetinX1
Organic Acids
Rosmarinic AcidX
Quinones
Coenzyme Q10X1
Vitamins
Vitamin CX1
Vitamin DXX2
Vitamin KX1
Vitamin B12X1
Pyrroloquinoline QuinoneX1

 


Informational References:

BioFoundations – Natural Substances that Enhance the Integrity and Function of the Neuroglia (Glial cells) (PDF)

Note: PDF files require a viewer such as the free Adobe Reader

Video:  Types of Neuroglia (Glial Cells) by AKLectures


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