The amino acid neurotransmitters, g

The amino acid neurotransmitters, glutamate and aspartate,
and many of their derivatives, are known as
excitatory amino acids. When present in excess, excitatory
amino acids can trigger a series of events leading
to neuronal damage and death (Fig. 1). Oxidative processes
are part of these events.3 One event is an increase
in intracellular Ca2/, which can lead to production of
free radicals from many sources, including the respiratory
burst of leukocytes, arachidonic acid release and
subsequent release of reactive oxygen species, and conversion
of xanthine dehydrogenase to xanthine
oxidase.3 In addition, influx of calcium leads to activation
of nitric oxide synthase,4 and high levels of intracellular
calcium are taken up by mitochondria,
where elevated calcium levels lead to production of
free radicals; when mitochondria are exposed to calcium
at the same concentration as that seen in neurons
exposed to excitotoxins, they generate hydroxyl and
carbon-centered radicals.5 Activation of the N-methylD-aspartate
(NMDA) receptor, considered one of the
most sensitive receptors to excitatory amino acids,
leads to elevation of lipid peroxidation in the hippocampus.6
Stimulation of NMDA receptors can also lead
to increases in intracellular nitric oxide, which rapidly
reacts with superoxide to form peroxynitrite, which can
be cytotoxic, and which is involved in tyrosine nitration
and formation of hydroxyl radical.7,8 However, recent
studies also indicate that NO and its donor compounds

ผลลัพธ์ (อังกฤษ) 2:

The amino acid neurotransmitters, glutamate and aspartate,
and many of their derivatives, are Known as
excitatory amino acids. When present in excess, excitatory
amino acids Can Trigger a Series of events Leading
to neuronal damage and Death (Fig. 1). Oxidative processes
are Part of these Events.3 One event is an increase
in intracellular Ca2 /, which Can Lead to Production of
free Radicals from many sources, including the respiratory
Burst of leukocytes, arachidonic acid release and
Subsequent release of Oxygen reactive species, and. conversion
of xanthine dehydrogenase to xanthine
Oxidase.3 In addition, Influx of calcium Leads to Activation
of nitric oxide synthase, 4 and High levels of intracellular
calcium are taken up by mitochondria,
where calcium levels Lead to Elevated Production of
free Radicals; when mitochondria are exposed to calcium
concentration at the Same as that seen in neurons
exposed to Excitotoxins, they Generate hydroxyl and
carbon-Centered Radicals.5 Activation of the N-MethylD-aspartate
(NMDA) receptor, considered one of the
Most receptors sensitive to. excitatory amino acids,
lipid peroxidation in the Leads to elevation of Hippocampus.6
Stimulation of NMDA receptors also Can Lead
to increases in intracellular nitric oxide, which rapidly
reacts with superoxide to form peroxynitrite, which Can
be cytotoxic, and which is involved in tyrosine nitration.
and Formation of hydroxyl Radical.7,8 However, recent
Studies also indicate that NO and its donor compounds.