Neurotransmitters are chemical substances which function as signal transmitters from a nerve ending to another cell or to a gland. They can belong to several different categories of neuro-chemicals including amino acids, monoamines and peptides. Within these categories, some of the most common neurotransmitters discovered by scientists include acetylcholine, dopamine, epinephrine, norepinephrine, serotonin, GABA and endorphins.
The basic functioning of a neurotransmitter:
The release of the neurotransmitters is triggered by the action potentials which travel through the nerves towards its ending. However, in some instances, the release of the neurotransmitters may take place when there is no action potential at the nerve endings as well. These neurotransmitters are stored in vesicles closer to the nerve ending membrane which is also known as the pre-synaptic membrane. The junction between the pre-synaptic membrane and the membrane of the nearby cell, nerve or gland is known as the synaptic cleft. Therefore, the membrane on the other side of the synaptic cleft will be named as the ‘post-synaptic’ membrane. The basic function of a neurotransmitter is to transmit the action potential or the signal from the pre-synaptic membrane to its post-synaptic membrane.
Following being released into the synaptic cleft, it will travel through it and will bind with the receptors attached to the post synaptic membrane. The biding will trigger the stimulation of the post-synaptic membrane. Following stimulation, the neurotransmitters will be released from its binding site and re-absorbed through the pre-synaptic membrane for further use.
Although this is the general functionality of a neurotransmitter, it is possible to distinguish between the functions of some of the main neurotransmitters from one another.
Specific functioning of some of the common neurotransmitters:
For instance, acetylcholine is the neurotransmitter which stimulates the muscles by activating the motor neurons. In addition, it is also thought to be responsible for regulating the areas of the brain which is responsible for arousal, learning, memory and attention.
When considering the neurotransmitter dopamine, it is considered to be responsible for voluntary movements of the body and the control of pleasurable emotions felt by a person.
The serotonin on the other hand seems to have a significant effect on emotions, mood, anxiety, regulating sleep, wakefulness as well as eating.
Among the neurotransmitters, epinephrine and norephinephrine is considered as excitatory neurotransmitters which is responsible for the ‘fight or flight’ reaction of animals. It raises the heart rate and the blood pressure in response to excitatory stimulations.
In contrast, the GABA or Gamma Aminobutyric acid inhibits over excitation of nerves and therefore certain regions in the brain.
When looking at all these different types of neurotransmitters and their various functions, it is apparent that its careful balance is essential for a normal mental and physical functioning. Thus, external influences on these neurotransmitters can alter the balance and therefore cause derangement in many bodily states.
