What are neurotransmitters?
The term neurotransmitter describes the usefulness of these messengers very well, because they are responsible for the interneuronal transmission - the transfer between the nerve cells.
Here, the term refers to the most diverse classes of substance, which are united under him only for their specific benefit. In the vernacular, neurotransmitters are often mistakenly equated with hormones.
However, hormones are substances that are released into the bloodstream, while neurotransmitters are limited to the action space between the synapses.
Medical & Health Functions, Tasks & Meanings
When a nerve cell is activated, neurotransmitters are released from the synapses at the end of the neuron into the so-called synaptic cleft.
The synaptic cleft is where two neurons "dock" to each other. When a neuron receives a signal, it goes through the entire length of the neuron to its end. To move on to the next neuron, a biochemical reaction takes place in the presynaptic cleft: Neurotransmitters are released from the synapse into the synaptic cleft.
Now these neurotransmitters can dock to receptors of the synapse of the next neuron and reshape the channels to open the ion channels for a short time. Calcium ions can now flow in, which changes the electrical potential of the neuron. So the signal is passed on.
The binding of the neurotransmitters to the synapse is, however, only conditionally permanent. Due to the polarization, the neurotransmitters are released again from the docking station of the synapse and are taken up again by the presynaptic neuron in the synaptic cleft.
There they remain, packed in so-called transport vesicles, until their next use. It must be remembered that this process takes place quickly, in a fraction of a second, considering the rate of conduction of signals in our nervous system. How quickly one perceives pain, how quickly one recognizes things, and how quickly one can react depends largely on the speed at which neurotransmitters are released into the synaptic cleft.
Diseases, complaints & disorders
Neurotransmitters thus occur within the nerve cells, at the synapses, where they are packed in transport vesicles waiting for their use. Such nerve cells are located both in the central nervous system (CNS) and in the peripheral nervous system.
The most common neurotransmitter in the peripheral nervous system is acetylcholine from the subgroup of Biogenic Amines. Glutamate is the most important neurotransmitter within the CNS. Other relevant neurotransmitters of the CNS are GABA, glycine, serotonin, norepinephrine and dopamine. Many of these neurotransmitters are already familiar to you in the context of certain drugs and that's no wonder:
Drug use has a special effect on the function of neurotransmitters in the brain. Thus, the stimulant causes amphetamine (in the "Speed" scene), the release of the neurotransmitters norepinephrine and dopamine. This causes a stimulation of the sympathetic, which then contributes to the onset of the fight-or-flight reflex. A strong wakefulness, vigilance and insensitivity to pain and hunger can be observed - just one of the reasons why amphetamine was used as a soldier's drug during the war.
Alcohol consumption also has an effect on the neurotransmitters or their receptors: Inhibition of the NMDA receptors and simultaneous stimulation of the GABA receptors inhibit the transmission of stimuli. Reactions are now slower, less controlled, the reaction rate is slowed down and environmental stimuli are no longer interpreted correctly.
Hallucinogens, such as LSD, also have a direct effect on the way in which neurotransmitters function. Neurotransmitters also have a strong impact on psychiatric illnesses such as acute schizophrenic psychosis. An acute psychosis is often based on overactivity of the neurotransmitter dopamine. Also, a pathological function of the neurotransmitter glutamate, is repeatedly hotly discussed as the cause of schizophrenia. The fact is that a psychosis can be counteracted by drugs that counteract the neurotransmitters.