Why are neurotransmitters important for the nerve impulse

Neurotransmitters: messenger substances in the brain

The place where nerve cells communicate with each other is the synaptic cleft. This is located between two ends of nerve cells, the so-called synapses. A synapse is structured as follows:

  • At the end of the nerve cell that transmits a signal to another is the presynaptic membrane.
  • The nerve cell that receives a signal has a so-called postsynaptic membrane.
  • The synaptic gap lies between these membranes.


Signal transmission in nerve cells © Axel Kock

An electrical nerve impulse cannot simply jump over this gap, but needs a “messenger” for its message. This is the job of the neurotransmitters. These biochemical transmitters are stored in small vesicles in the presynaptic nerve endings. An electrical signal sets them free. As a result, they reach the adjacent nerve cell via the synaptic gap. There the chemical is translated back into an electrical signal. All of this happens in a few milliseconds. The neurotransmitter is then broken down again or transported back to the original nerve cell and taken up there (resumption, reuptake). Typical neurotransmitters are e.g. serotonin, noradrenaline and dopamine. However, there are also neurotransmitters that inhibit signal transmission, such as GABA.