bout 50 neurotransmitters have been discovered so far. Out of these, a few of the most important neurotransmitters and their functions are discussed below.
- This neurotransmitter was discovered in the year 1921, by Otto Loewi.
- It is mainly responsible for stimulating muscles.
- It activates the motor neurons that control the skeletal muscles.
- It is also concerned with regulating the activities in certain areas of the brain, which are associated with attention, arousal, learning, and memory.
- People with Alzheimer’s disease are usually found to have a substantially low level of acetylcholine.
- Dopamine is the neurotransmitter that controls voluntary movements of the body, and is associated with the reward mechanism of the brain. In other words, dopamine regulates the pleasurable emotions.
- Drugs like cocaine, heroin, nicotine, opium, and even alcohol increase the level of this neurotransmitter.
- A significantly low level of dopamine is associated with Parkinson’s disease, while the patients of schizophrenia are usually found to have excess dopamine in the frontal lobes of their brain.
- Serotonin is an important inhibitory neurotransmitter, which can have a profound effect on emotion, mood, and anxiety.
- It is involved in regulating sleep, wakefulness, and eating.
- It plays a role in perception as well.
- The hallucinogenic drugs like LSD actually bind to the serotonin receptor sites, and thereby block the transmission of nerve impulses, in order to alter sensory experiences.
- A significantly low level of serotonin is believed to be associated with conditions like depression, suicidal thoughts, and obsessive compulsive disorder. Many antidepressants work by affecting the level of this neurotransmitter.
Gamma-aminobutyric Acid (GABA)
- GABA is an inhibitory neurotransmitter that slows down the activities of the neurons, in order to prevent them from getting over excited.
- When neurons get over excited, it can lead to anxiety. GABA can thus help prevent anxiety.
- It is a non-essential amino acid, that is produced by the body from glutamate.
- A low level of GABA can have an association with anxiety disorders.
- Drugs like Valium work by increasing the level of this neurotransmitter.
- Glutamate is an excitatory neurotransmitter that was discovered in 1907 by Kikunae Ikeda of Tokay Imperial University.
- It is the most commonly found neurotransmitter in the central nervous system. Glutamate is mainly associated with functions like learning and memory.
- An excess of glutamate is however, toxic for the neurons.
- An excessive production of glutamate may be related to the disease, known as amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease.
Epinephrine and Norepinephrine
- Epinephrine (also known as adrenaline) is an excitatory neurotransmitter, that controls attention, arousal, cognition, and mental focus.
- Norepinephrine is also an excitatory neurotransmitter, and it regulates mood and physical and mental arousal.
- An increased secretion of norepinephrine raises the heart rate and blood pressure.
- Endorphins are the neurotransmitters that resemble opioid compounds, like opium, morphine, and heroin in structure.
- The effects of endorphins on the body are also quite similar to the effects produced by the opioid compounds. In fact, the name ‘endorphin’ is actually the short form for ‘endogenous morphine’.
- Like opioids, endorphins can reduce pain, stress, and promote calmness and serenity. The opioid drugs produce similar effects by attaching themselves to the endorphin receptor sites.
- Endorphins enable some animals to hibernate by slowing down their rate of metabolism, respiration, and heart rate.