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Blood can carry a number of ingested toxins, however, which would induce significant neuron death if they reach nervous tissue. Thus, protective cells termed astrocytes surround the capillaries in the brain and absorb nutrients from the blood and subsequently transport them to the neurons, effectively isolating the brain from a number of ...
In some cases the level or exposure-time may be critical, with some substances only becoming neurotoxic in certain doses or time periods. Some of the most common naturally occurring brain toxins that lead to neurotoxicity as a result of long term drug use are amyloid beta (Aβ), glutamate, dopamine, and oxygen radicals.
Excitotoxicity can occur from substances produced within the body (endogenous excitotoxins).Glutamate is a prime example of an excitotoxin in the brain, and it is also the major excitatory neurotransmitter in the central nervous system of mammals. [14]
The blood–brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that regulates the transfer of solutes and chemicals between the circulatory system and the central nervous system, thus protecting the brain from harmful or unwanted substances in the blood. [1]
It has no known function for clostridia in the soil environment where they are normally encountered. It is also called spasmogenic toxin , tentoxilysin , tetanospasmin , or tetanus neurotoxin . The LD 50 of this toxin has been measured to be approximately 2.5–3 ng/kg, [ 2 ] [ 3 ] making it second only to the related botulinum toxin (LD 50 2 ...
Toxic encephalopathy is a neurologic disorder caused by exposure to neurotoxic organic solvents such as toluene, following exposure to heavy metals such as manganese, as a side effect of melarsoprol treatment for African trypanosomiasis, adverse effects to prescription drugs, or exposure to extreme concentrations of any natural toxin such as cyanotoxins found in shellfish or freshwater ...
The blood–brain barrier is a structure composed of endothelial cells and astrocytes that forms a barrier between the brain and circulating blood. Physiologically, this enables the brain to be protected from potentially toxic molecules and cells in the blood.
The larger arteries throughout the brain supply blood to smaller capillaries. These smallest of blood vessels in the brain, are lined with cells joined by tight junctions and so fluids do not seep in or leak out to the same degree as they do in other capillaries; this creates the blood–brain barrier. [44]