Neurotransmitters and their relationship with anxiety, depression and aggressiveness

Neurotransmitters and their relationship with anxiety, depression and aggressiveness

The brain cells are neurons and the communication between these nerve cells has certain characteristics, one of them is that they almost never touch each other, although they are separated by tiny spaces.

The zone of interaction of neurons is called a synapse that means union-link, and communication between neurons is carried out by means of neurotransmitters. All the actions of the brain such as ordering the muscles to contract and relax in a coordinated way to carry out a simple movement, intellectual tasks, etc., are transmitted by them and are able to modulate our emotions.


  • 1 Limbic System and emotions
  • 2 The conversation between neurons
  • 3 The chemical neurotransmitters
  • 4 How neurotransmitters are released
  • 5 The receivers
  • 6 Interferences in neuronal communication
  • 7 Natural anxiety and pathological anxiety
  • 8 Depression
  • 9 Aggression and passivity, also depend on the chemistry of the brain

Limbic System and emotions

The limbic system It has great importance in the origin and control of emotions. And within this great circuit, a small region, the hypothalamus, is associated with many emotional behaviors and functions such as hunger and thirst. It has been observed that when some nuclei of the hypothalamus are destroyed, the subject can stop eating and even even starve in the middle of the most appetizing meal. Through this core is that you feel the need to eat. This region of the hypothalamus is known as the center of satiety.

In the hypothalamus and other areas of the limbic system, the cell nuclei are located that, when stimulated, provoke responses of cholera and aggressiveness in animals.

The conversation between neurons

Neurons have two types of extensions, branched ones, which give these cells their characteristic starry or arborized appearance, and other longer and simpler ones, the axons, which are those through which neurons communicate with each other. The final part of the axon, which establishes communication with the adjacent neuron, is called a synaptic terminal or presinapsis, and is identified in a large number of synapses by the very characteristic presence of spherical structures: synaptic vesicles.

Inside the nerve cells predominates potassium and some proteins also with electric charge while outside there is a high concentration of sodium and chlorine. When the neuron is "quiet" its interior is more electrically negative than the exterior, but this situation changes abruptly when the neuron communicates with other neurons. Neurotransmitters are the communicators of the relationship between neurons.

Chemical neurotransmitters

It is usually simple substances. Considering the huge number of contacts that are established between neurons, it is surprising how small the number of molecules that nature has designed to transmit hundreds of thousands of messages between neurons. The neurotransmitters They can be classified, from the point of view of their structure, into three main groups: amino acids, amines and peptides.

How neurotransmitters are released

Neurotransmitters are expelled from the presynaptic neuron to carry the message to the postsynaptic. Neurotransmitters are stored in the characteristic structures of presynapsis, synaptic vesicles, and remain there kidnapped until calcium causes them to leave on the way to the neuron to which they have to transmit the message.


The contact of the receiver with the transmitter originates the message that neurons recognize, that is, a change in cellular permeability to a certain ion and the consequent change in the distribution of electrical charges.

Post-synaptic receptors play a key role in behavioral physiology. The receptors of the same neurotransmitter are not always the same, they have differences in their structure that force them to think that they are different molecules. Once the message has been transmitted, the neurotransmitter, already finished its function, must stop interacting with the receiver and disappear from the synaptic space so that a new communication can be initiated, if necessary. There are two types of actions that allow this to happen: the neurotransmitter is destroyed, that destroyed transmitter is transported back to the neurons.

Interferences in neuronal communication

The neurotransmitter exit process can be altered, with substances that close the entrance of the calcium channels, thus intercepting the signal to release the neurotransmitter. Another way to modify the neurotransmitter release process is to prevent its entry into the synaptic vesicles. Some toxins, such as black widow venom, increase the outflow of vesicle neurotransmitters in an extraordinary and indiscriminate way, thereby altering the normal mechanisms of communication, in particular that of neurons with muscles. Death by botulism It is because the toxin prevents the release of neurotransmitters.

Receptors, that is, the proteins with which neurotransmitters interact, can also be affected by substances, some natural, others synthesized in the laboratory.

Natural anxiety and pathological anxiety

Anxiety is a natural condition. At the biological level, considered as a superalerta state, is a key element for the survival of the individual. Anxiety, with all its organic characteristics (light tremor, palpitations, cold hands, sweating). Anxiety can also become a pathological response.

Anxiety can be manipulated through some of the neuron receptors

The most effective anxiolytics are compounds known as benzodiazepines. In addition to their anxiolytic effect, benzodiazepines are also used as auxiliaries in the control of sleep, and contribute in this way, although indirectly, to reduce anxiety. It is known by all the lack of sleep is a powerful cause of anxiety and that the problems get worse during the hours of insomnia. The effect of benzodiazepines and barbiturates, is to increase the effectiveness of this process of entry of chlorides to neurons. The presence in the brain of these receptors to benzodiazepines, which are man-made artificial substances, suggests the existence of a "natural benzodiazepine", that is, the substance that is rightfully the owner of the benzodiazepine site in the receptor.

The Depression

Fluctuations in mood do not affect daily organic functions such as eating or sleeping. Nor do they infer in their work activities, their intellectual performance and their relationships with other individuals. Endogenous depression is a disease as real as pneumonia. People suffering from depression, behavior patterns may appear on a recurring basis, that is, disappear for a while and then repeat with very similar characteristics. The symptoms are lack of motivation, lack of interest in activities that previously seemed attractive, passivity, lack of concentration. Some depressive patients lose weight significantly, while others on the contrary, gain weight. In some, insomnia is common while others spend most of their time asleep. There are patients who are agitated and restless, and others can barely get out of bed. In more advanced stages they can occur psychic disorders such as hallucinations or feelings of paranoia; The number of suicides in depressive patients is very high.

In Bipolar Disorder, many patients respond well to pharmacological treatments with medications that in their structure and for their effects, have a relationship with the neurotransmitters of the group called biogenic amines.

The Lithium It is also used as maintenance therapy to prevent recurrence of depression and mania in this disorder; Lithium decreases the severity, duration and recurrence of episodes of mania and depression in bipolar disorders.

Aggression and passivity, also depend on the chemistry of the brain

Aggression is the result of the function of neurons integrated in circuits. At least six areas in the brain related to aggression are currently known, of which the most important are the amygdala and the hypothalamus, which are part of the limbic system. The first is related to a predatory attitude, the second refers to defensive behavior. In these two cases, aggressive behavior manifests itself towards an individual of a different species. A third type of aggressive behavior is the so-called social aggressiveness. This type of behavior is manifested within a colony between individuals of the same species. In many cases this type of aggressive behavior is restricted to males and has a clear link with the activity of the male hormone, testosterone.

Evelin Doriana Castañeda Gutiérrez


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