The Messengers Of The Brain Are Here! A Dive Into Their World...

Neurotransmitters

Photo by Stefano Bucciarelli on Unsplash

Inside the brain, there are networks of neurons for transferring signals. Neuronal ends do not attach. There is a gap between the end of a neuron and the next cell (the target). This gap is known as the synaptic cleft. So, how will the signal travel through this fluid-filled space? The answer is neurotransmitters. 

Neurotransmitters are chemicals that are responsible for the transfer of signals. The transfer of signals is from a neuron to target cells (neurons, muscles, or glands). These chemical messengers are in the thin-walled sacs called synaptic vesicles at the ends of the axons called axon terminals. Axons are the long cylindrical part of a neuron.   

Signal transfer mechanism: 

When a signal reaches the terminals, the vesicles fuse with the neuron’s membrane. It releases the neurotransmitters into the cleft. The transmitters travel through the synaptic cleft to reach the target. The target has receptors on its membrane to receive the neurotransmitters. 

According to Dale’s law, specific neurons release similar neurotransmitters. Modern notion considers the idea of neurotransmitter switching. It suggests that some neurons can change the type of neurotransmitters based on different circumstances. However, each neurotransmitter has a specific receptor. They fit into the receptors, similar to a key that fits in a lock. 

After binding, they cause a trigger in the target neuron, causing the respective action to follow: the initiation of another signal. 

The trigger can have three effects: 

1. Excitatory: This causes a signal or excitation of the target cell. Example: glutamate and epinephrine.

2. Inhibitory: This prevents or blocks the signal from proceeding further. Example: glycine and gamma-aminobutyric acid(GABA).

3. Modulatory: This adjusts the signals at the synapse and affects several neurons. Example: dopamine.  

On completion of its task, the neurotransmitter faces one of three fates:

1. It can fade with the process of diffusion.

2. It can be reabsorbed and reused by the process of reuptake.

3. It can be broken through degradation by enzymes.

Through their role of conducting signals, neurotransmitters support nearly all the functions of an organism. There are more than 60 types of neurotransmitters found in the human brain. Each has its importance. Here is a table mentioning some neurotransmitters with their functions.

Thus, neurotransmitters are messengers that help signal transmission for various bodily functions and regulate cognitive functions such as mood, attention, learning, and memory, as well as crucial functions like heart rate and blood pressure. Their knowledge can help in better perception and understanding of ourselves.