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Neurotransmitters
What is Neurotransmitter?
A neurotransmitter is a chemical messenger that carries, boosts and modulates signals between neurons and other cells in the body. In most cases, a neurotransmitter is released from the axon terminal after an action potential has reached the synapse. The neurotransmitter then crosses the synaptic gap to reach the receptor site of the other cell or neuron. Then, in a process known as reuptake, the neurotransmitter attaches to the receptor site and is reabsorbed by the neuron.
Neurotransmitters play a major role in everyday life and functioning. Scientists do not yet know exactly how many neurotransmitters exist, but more than 100 chemical messengers have been identified. When neurotransmitters are affected by disease or drugs, there can be a number of different adverse effects on the body. Diseases such as Alzheimer's, Parkinson's, and Autism are associated with deficits in certain neurotransmitters.
Types of Neurotransmitters
Neurotransmitters can be classified by function:
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Excitatory neurotransmitters: These types of neurotransmitters have excitatory effects on the neuron; they increase the likelihood that the neuron will fire an action potential. Some of the major excitatory neurotransmitters include epinephrine and norepinephrine.
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Inhibitory neurotransmitters: These types of neurotransmitters have inhibitory effects on the neuron; they decrease the likelihood that the neuron will fire an action potential. Some of the major inhibitory neurotransmitters include serotonin and GABA
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Some neurotransmitters, such as acetylcholine and dopamine, can both excitatory and inhibitory effects depending upon the type of receptors that are present.
They can also be categorized as one of six types:
- Acetylcholine
- Amino acids: Gamma-aminobutyric acid (GABA) and Glycine Glutamate Aspartate.
- Neuropeptides: Oxytocin,endorphins, vasopressin, etc.
- Monoamines: Epinephrine, norepinephrine, histamine, dopamine and serotonin.
- Purines: Adenosine, ATP.
- Lipids and gases: Nitric oxide, cannabinoids.
Identifying Neurotransmitters
The actual identification of neurotransmitters can actually be quite difficult. While scientist can observe the vesicles containing neurotransmitters, actually figuring out what chemicals are stored in the vesicles is not quite so simple. Because of this, neuroscientists have developed a number of guidelines for determining whether or not a chemical should be called a neurotransmitter:
- The chemical must be produced inside the neuron
- The necessary precursor enzymes must be present in the neuron
- There must be enough of the chemical present to actually have an effect on the postsynaptic neuron
- The chemical must be released by the presynaptic neuron, and the postsynaptic neuron must contain receptors that the chemical will bind to
- There must be a reuptake mechanism or enzyme present that stops the action of the chemical
What is Nueron?
A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are similar to other cells in the human body in a number of ways, but there is one key difference between neurons and other cells. Neurons are specialized to transmit information throughout the body.
These highly specialized nerve cells are responsible for communicating information in both chemical and electrical forms. There are also several different types of neurons responsible for different tasks in the human body.
Sensory neurons carry information from the sensory receptor cells throughout the body to the brain. Motor neurons transmit information from the brain to the muscles of the body. Interneurons are responsible for communicating information between different neurons in the body.
Neurons vs. Other Cells
Similarities with other cells:
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Neurons and other body cells both contain a nucleus that holds genetic information.
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Neurons and other body cells are surrounded by a membrane that protects the cell.
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The cell bodies of both cell types contain organelles that support the life of the cell, including mitochondria, Golgi bodies, and cytoplasm.
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Differences that make neurons unique:
Unlike other body cells, neurons stop reproducing shortly after birth. Because of this, some parts of the brain have more neurons at birth than later in life because neurons die but are not replaced. While neurons do not reproduce, research has shown that new connections between neurons form throughout life.
Neurons have a membrane that is designed to sends information to other cells. The axon and dendrites are specialized structures designed to transmit and receive information. The connections between cells are known as a synapses. Neurons release chemicals known as neurotransmitters into these synapses to communicate with other neurons.
The Structure of a Neuron
There are three basic parts of a neuron: the dendrites, the cell body and the axon. However, all neurons vary somewhat in size, shape, and characteristics depending on the function and role of the neuron. Some neurons have few dendritic branches, while others are highly branched in order to receive a great deal of information. Some neurons have short axons, while others can be quite long. The longest axon in the human body extends from the bottom of the spine to the big toe and averages a length of approximately three feet!
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About Dr. Lu
Dr. Lu completed his medical education and training in China. (The Chinese Academy of Medical Sciences and Shandong University Medical College respectively) Over 20 years clinic and research experiences in both medical school and hospital, Dr. Lu learned both West Medicine and Traditional Chinese Medicine including modern medical technology, acupuncture, medicinal herbs, and specializing in neurology. After years practice and accomplishments in China, Dr. Lu was invited as a visiting professor at the University of South Carolina, School of Medicine in 1991. After excellent achievements in research program funded by NIH and NSF, Dr. Lu decided to become a Doctor of Chiropractic in order to introduce the Traditional Chinese Medicine to the Western culture. Obtained Doctor Degree of Chiropractic from Parker College of Chiropractic, Dr. Lu became a licensed Doctor of Chiropractic and Board Permit in Acupuncture, then began his practice in Dallas Texas since then. Dr. Lu learned NAET and became a NAET Instructor in 2003 and 2014 respectively. In 2007 Dr. Lu was voted the best Acupuncturist in the City of Richardson by Living Magazine. In 2013, Dr. Lu was rated the Best Chiropractor in City of Plano. In 2014 advanced to America's Top Chiropractors specialized in Natural Medicine. |
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