The human brain is filled with billions of cells that receive and send signals every second. Those signals affect everything about us, including the emotions we feel and the memories we form. When we receive fresh information, nerve cells swoop into action immediately, transmitting electrical signals which trigger the release of certain chemicals. These chemicals are referred to as neurotransmitters and they are released at specific locations known as synapses.
The neurotransmitters function like messengers as they go about their business of transmitting information that affect nearby cells. Knowing how nerve cells communicate can be extremely crucial for understanding how brain diseases and disorders come about. That is why researchers work tirelessly, hoping to learn how malfunctions in the cell communication chains might result in or contribute to brain disorders.
With that kind of knowledge, modern medicine will be in a better position to prevent and treat certain diseases of the brain. Scientists have been able to track cell communication better than ever due to the new tools and improved technologies in cellular and molecular biology that are now available.
How nerve impulses work
Nerve impulses are facilitated by ion channels as they open and close. Ion channels are molecular tunnels that are filled with water and are selectively permeable. Found to be passing through the cell membrane, they permit small molecules and ions to gain entry into cells as well as exit the cells. As ions flow through cells, an electrical current is created, resulting in small voltage changes across the cell membrane of the neuron.
The difference in charge between the outside and inside of the cell will determine how capable a neuron is of generating an electrical impulse. As a nerve impulse starts, the neuron changes from being in a state of internal negative charge to being in the state of a positive charge. This dramatic change is referred to as an action potential. It is due to this that a neuron has the ability to fire multiple impulses in a second. These voltage changes actually travel as fast as many hundred miles per hour along the axon’s membrane.
Neurotransmitters get triggered
The brain’s neurotransmitters are triggered to be released when the voltage changes get to the end of the axon. Neurotransmitters diffuse across the synapse once they are released at nerve terminals, before they get to the surface of the target cell where they bind to receptors. While it could be a gland cell or a muscle cell, usually, this would be another neuron.
The receptors behave like a switch of sorts to turn on or off the next cell. A neurotransmitter fits snugly into a region of the receptor that is programmed to recognise only a specific chemical messenger. This interaction then triggers the target cell to respond in a certain way. Such a response could be the stimulation of enzyme activity, the contraction of a muscle, the generation of an action potential, or the inhibition of neurotransmitter release.
Types of Neurotransmitters
Neurotransmitters are believed to be of many different types, running into several hundreds. However, they have been separated into three major categories.
Biogenic amine neurotransmitters
This category of neurotransmitters is the best understood and the longest studied, and it is further divided into six major categories including acetylcholine, histamine, dopamine, epinephrine, norepinephrine, and serotonin.
While acetylcholine is thought to be connected with memory, learning, and muscle activation, histamine is released in response to allergic reactions and is believed to play a role in learning, attention, and arousal. Dopamine has been linked to addiction, reinforcement, reward, motivation and body movement, while epinephrine is a stress hormone as much as it is a neurotransmitter. Norepinephrine affects alertness and sleep, and serotonin has been found to play a role in modulating sexuality, appetite, sleep, mood, and anxiety.
These are thought to be connected with mediation of many functions including the regulation of mood, stimulation of appetite, and the perception of pain. The development of Alzheimer’s, disease, Huntington’s disease, eating disorders, and schizophrenia has been associated with abnormalities in peptide neurotransmitters.
Amino acid neurotransmitters
Some experts believe these neurotransmitters are the primary players in the neurotransmission process. The two main amino acid neurotransmitters are glutamate and gamma-aminobutyric acid (GABA). Glutamate, which Is the brain’s most abundant chemical messenger is an excitatory neurotransmitter. GABA is a major inhibitory neurotransmitter and is crucial for balancing the brain’s excitation.
Research on neurotransmitters
Scientists have intensively researched neurotransmitters in order to understand how the work. The goal of such research is often to understand the effects drugs have on these brain chemicals. With the kind of studies undertaken in the field, the hope is that we can learn more about the circuits responsible for brain disorders. We can also learn more about the functions of the human brain, such as how it stores memories.
So far, studies have found that psychiatric disorders such as schizophrenia and neurological disorders such as Parkinson’s and Alzheimer’s can be traced to deficits in the release and production of neurotransmitters. With insights like these and more to follow, scientists can be guided to come up with new, more powerful drugs to treat a wide range of brain disorders.
Interconnectivity between brain cells
All neurotransmitters are immensely interconnected as they are part of an elaborate system of checks and balances functioning at every point in time. They are so interconnected that other parts of the system won’t function properly if one part is down.
What is cell communication?
A process whereby a cell responds to neighbouring signals.
How do cells in the brain communicate with each other?
Through the actions of electric signals.
What are the cells of the brain called?
What are the three types of cell communication?
Surface membrane to surface membrane, exterior, and direct communication.
What are the three main stages of cell signalling?
Reception, transduction, and response.
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