Synaptic Transmission refers to the process by which information is communicated between neurons (nerve cells) in the nervous system. It involves the transfer of chemical signals, known as neurotransmitters, across the synapse, which is the small gap between two neurons.

Electrical Signal Conversion:

The synaptic transmission begins when an electrical signal, known as an action potential, travels down the axon (a long slender extension) of the presynaptic neuron. This action potential causes the release of neurotransmitters from vesicles in the presynaptic terminal.

Neurotransmitter Release:

Upon reaching the presynaptic terminal, the action potential triggers the opening of voltage-gated calcium channels. This influx of calcium ions into the presynaptic terminal triggers the fusion of neurotransmitter-containing vesicles with the cell membrane, resulting in the release of neurotransmitters into the synapse.

Synaptic Cleft:

Once released into the synapse, the neurotransmitters diffuse across the synaptic cleft, which is the small gap between the presynaptic and postsynaptic neurons. The synaptic cleft is filled with extracellular fluid that allows for the efficient movement of neurotransmitters.

Neurotransmitter Receptor Binding:

On the postsynaptic neuron, there are specific membrane-bound receptors that recognize and bind to the neurotransmitters released from the presynaptic neuron. The binding of neurotransmitters to these receptors initiates a series of biochemical processes within the postsynaptic neuron.

Signal Transmission:

Upon binding to the receptors, the neurotransmitters can either excite or inhibit the postsynaptic neuron. Excitatory neurotransmitters increase the likelihood of the postsynaptic neuron generating an action potential, while inhibitory neurotransmitters decrease this likelihood.

Termination of Signal:

The synaptic transmission is a transient process, and it needs to be carefully regulated. To terminate the signal, the neurotransmitters can be removed from the synaptic cleft through various mechanisms. Some neurotransmitters are actively taken up by presynaptic neurons or neighboring glial cells, while others are broken down by enzymes in the synaptic cleft.

Importance and Modulation:

Synaptic transmission plays a critical role in the function of the nervous system, allowing for information processing and communication between neurons. The strength and effectiveness of synaptic transmission can be modulated by factors such as the amount of neurotransmitters released, the number of available receptors, and the activity of regulatory molecules.


In summary, synaptic transmission is a complex process that enables neurons to communicate and transmit information. It involves the release, diffusion, and recognition of neurotransmitters, leading to the modulation of electrical signals and ultimately influencing neuronal activity and behavior.