Neurotransmitter Definition

“Neurotransmitter is a type of chemical messenger that transmits signals across a chemical synapse, from one neuron to another.”

What is Neurotransmitter?

A neurotransmitter is the body’s chemical messenger. They are molecules that transmit signals from neurons to muscles, or between different neurons. The transmission of signals between two neurons occurs in the synaptic cleft. The electrical signals that travel along the axon are briefly converted into chemical signals through neurotransmitters.

Also Read: Reflex Action


Types of Neurotransmitter

There are the following different types of neurotransmitter:

Excitatory Neurotransmitters

These type of neurons increase the chances of the neuron firing an action potential. Epinephrine and norepinephrine are the two excitatory neurotransmitters.

Inhibitory Neurotransmitters

These have inhibitory effects on the neurons and have fewer chances of the neuron firing an action potential. For eg., serotonin and gamma-aminobutyric acid (GABA).

Modulatory Neurotransmitter

These can affect a large number of neurotransmitters at the same time. These can also influence the effect of other chemical messengers.

Other Types of Neurotransmitter

Types Examples
Amino acids

Gama amino-butyric acid


Peptides Oxytocin








Purines Adenosine

Adenosine Triphosphate


Nitric oxide

Carbon monoxide

Acetylcholine Acetylcholine

Also Read: Difference between neurons and neuroglia

How can you Identify a Neurotransmitter?

The following guidelines should be followed to identify whether the chemical is a neurotransmitter or not:

  • The chemical should be produced inside the neuron.
  • The neuron should contain the necessary precursor enzymes.
  • It should be regulated and controlled.
  • The chemical should be released by the presynaptic neuron and bind on the receptors present on the post-synaptic neuron.

Neurotransmitter Diseases

The neurotransmitter diseases affect how the neurotransmitters are synthesised, transported and broken down in the brain.

The common neurotransmitter diseases include:

  • Parkinson’s disease
  • Alzheimer’s disease
  • Depression

Neurotransmitter diseases are genetically inherited from their parents. These are diagnosed by examining the cerebrospinal fluid collected from the spinal column.

How is the Activity of the Neurotransmitter Stopped?

The activity of the neurotransmitter can be stopped in the following ways:

  • The enzymes can help in deactivating the neurotransmitter.
  • It can move away from the receptor.
  • It can be taken back by the neuron.

Also Read: Nervous System

For more information on what is a neurotransmitter, its definition, types and functions, keep visiting BYJU’S website or download BYJU’S app for further reference.

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