The nervous system is made up of neurons and non-neuronal cells, glial cells.
Neurons are highly specialized cells for the processing and transmission of
cellular signals and are key components of the brain and spinal cord. The
structure of a typical neuron consists of a cell body called soma, a long thin
axon which is covered by the myelin sheath, and around the cell body there are
branching dendritic trees that receive signals from other neurons. SABiosciences
provides PCR arrays to profile different neurotransmitters, neurotrophins, ion
channels, neurogenesis processes, etc. See details here.
In vertebrates, the nervous system consists of central nervous system (CNS)
and peripheral nervous system (PNS). The central nervous system contains the
brain and spinal cord. White matter is one of the two components of the CNS and
consists mostly of myelinated axons whereas grey matter consists of neuronal
cell bodies, dendrites, glial cells, and blood vessels. The brain and spinal
cord are isolated from the rest of the body by the blood-brain barrier (BBB),
which prevents most types of macromolecules from going into the interior of the
CNS.
The main function of the PNS is to connect the CNS to the limbs and organs.
The peripheral nervous system is divided into the somatic nervous system and the
autonomic nervous system. The somatic nervous system processes sensory
information and controls all voluntary muscular systems within the body through
the action of skeletal muscles. The autonomic nervous system mediates
involuntary activities such as heartbeat and breathing. It sends fibers to three
tissues: cardiac muscle, smooth muscle, and glandular tissue. The autonomic
nervous system is divided into the sympathetic nervous system and
parasympathetic nervous system. The sympathetic nervous system is always active
at a basal level and becomes more active during times of stress. It functions in
actions requiring quick responses. The parasympathetic nervous system, quite
opposite to the sympathetic nervous system, makes the body to rest and digest.
The signals are produced and propagated by ions that create an action
potential (a short-term change in the electrical potential on the surface of a
cell) that moves along the neuron. Within the neuron membrane there are gated
ion channels that vary in type. The fast response channels are sodium (Na+)
channels that are voltage-gated and are used to send rapid signals. Signals can
be also generated and propagated by other charge-carrying ions, including
potassium (K+), chloride (Cl-), and calcium (Ca2+). Ion channels can be also
classified by gating, i.e. by what opens and closes the channels. Voltage-gated
ion channels open or close depending on the voltage gradient across the plasma
membrane, while ligand-gated ion channels open or close depending on binding of
ligands to the channel. SABiosciences' Neuroscience Ion Channels and
Transporters PCR array can be used to profile different ion channels and
membrane transporters in your samples.
Neurons communicate with one another through synapses. Synapses are
functional connections between neurons or between neurons and other types of
cells. Though there are chemical, electrical, and immunological synapses, in
most contexts, a "synapse" usually means chemical synapse. Most
synapses connect axons to dendrites. Synapses pass information directionally
from a presynaptic cell to a postsynaptic cell. The presynaptic terminal
contains neurotransmitters enclosed in small membrane-bound spheres called
synaptic vesicles whereas the postsynaptic cell contains neurotransmitter
receptors. Between the pre- and post-synaptic cells there is a gap about 20 nm
wide called synaptic cleft. The membranes of the two adjacent cells are held
together by cell adhesion proteins. Once released, the neurotransmitters are
rapidly taken up by the next neuron. Neurons differ in the type of
neurotransmitter they manufacture and can be classified as cholinergic,
GABAergic, glutamatergic, dopaminergic, and serotonergic neurons. SABiosciences'
Neurotransmitter Receptors and Regulators PCR array can be used to study the
mRNA expression of different neurotransmitters.
Neurotrophins are a family of growth factors that promote the survival of
neurons and induce differentiation of progenitor cells to form neurons. They
include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF),
neurotrophin-3(NT-3), neurotrophin-4 (NT-4), and novel neurotrophin-1 (NNT1).
There are two classes of receptors for neurotrophins: p75 and the "Trk"
family of tyrosine kinases receptors. SABiosciences' Neurotrophins and Receptors
PCR array is a great tool for neurotrophin profiling.
Glial cells are non-neuronal cells and function as partners to neurons. They
surround neurons and hold them in place, supply nutrients and oxygen to neurons,
insulate one neuron from another, and destroy pathogens and remove dead neurons.
The glial cells can be divided into two categories: microglia and macroglia.
Microglia cells are specialized mobile macrophages derived from hematopoietic
precursors and capable of phagocytosis in brain and spinal cord. Macroglia cells
are bigger. The most abundant type of macroglial cells are astrocytes.
Oligodendrocytes are another type of macroglia cells that coat axons in the CNS
with their cell membrane forming a specialized membrane differentiation called
myelin. Similar to oligodendrocytes, Schwann cells provide myelination to axons
in the PNS.
In vertebrates, the landmarks of embryonic neural development include the
derivation and differentiation of neurons from stem cell precursors, the
migration of immature neurons from their birthplaces in the embryo to their
final positions, outgrowth of axons from neurons and guidance of the motile
growth cone through the embryo towards postsynaptic partners, the generation of
synapses between these axons and their post-synaptic partners, and finally the
lifelong changes in synapses which are presumed to underlie learning and memory.
New neurons are continually born throughout adulthood in predominantly two
regions of the brain: the subventricular zone lining the lateral ventricles,
where the new cells migrate to the olfactory bulb; and the subgranular zone,
which is part of the dentate gyrus of the hippocampus. SABiosciences provides
Neurogenesis and Neural Stem Cell PCR array to study elements involved in
neurogenesis process.
There are some intensively studied neurological disorders: Alzheimer's disease,
Parkinson's disease, multiple sclerosis, autism, and depression. Alzheimer's
disease is a neurodegenerative disease characterized by progressive cognitive
deterioration together with declining activities of daily living and behavioral
changes. The amyloid (an insoluble fibrous protein in the cells) hypothesis
suggests an amyloid-related mechanism that neuronal connections in the brain in
the fast-growth phase of early life may be affected by aging-related processes
in later life to cause neuronal death. SABiosciences' Alzheimer's Disease PCR
array can be used to explore the aberrant changes of different genes.
Parkinson's disease is another neurodegenerative disease caused by the
insufficient formation and action of dopamine which is produced in the
dopaminergic neurons of the brain. It is a movement disorder characterized by
muscle rigidity, tremor, and physical movement disability. Multiple sclerosis
(MS) is another form of neurodegenerative disease. The name multiple sclerosis
refers to scars in the white matter of the brain and spinal cord. Demyelination
or the loss of the myelin sheath insulating the nerves leads to MS. In MS, the
body's own immune system attacks and damages the myelin. When myelin is lost,
the axons can no longer effectively conduct signals. Autism is a genetic
disease, although the genetics of autism is complex and unclear. It is
distinguished by a characteristic triad of symptoms: impairments in social
interaction; impairments in communication; and restricted interests and
repetitive behavior. The general term "depression" is often used to
describe the major depressive disorder. The understanding of the nature and
causes of depression indicates biological, hereditary, psychological, and social
origins. Most anti-depressant medications increase the levels of one or more
monoamines - the neurotransmitters serotonin, norepinephrine, and dopamine - in
the synaptic cleft between neurons in the brain.
SABiosciences' cataloged or customized PCR arrays provide a powerful tool to
study the mechanisms involved in the complicated neuron activities and
disorders.
