Postsynaptic Cell

What is a Postsynaptic Cell?

A postsynaptic cell is the receiving cell at a synapse. It may be a neuron or a non-neuronal target, such as a muscle cell. Chemical synapses use neurotransmitters; electrical synapses pass current directly between cells. In this context, the neuron sending the signal is known as the presynaptic cell. At a chemical synapse, the postsynaptic cell receives chemical signals, in the form of neurotransmitters, from the presynaptic cell, which can either excite or inhibit the postsynaptic cell, thereby affecting its activity.

Key Features

• Dendrites and Soma

  The dendrites and soma (cell body) of the neuron often serve as the main postsynaptic sites. These areas contain receptors that are activated by neurotransmitters released from the presynaptic neuron.

• Postsynaptic Density

  The postsynaptic density is a specialized protein structure associated with the inner face of the postsynaptic membrane, particularly prominent at excitatory synapses. It organizes receptors, scaffolding proteins, and signaling molecules. This region plays a key role in receiving and processing signals from the presynaptic neuron.

• Neurotransmitter Receptors

  Receptors located on the postsynaptic membrane bind to neurotransmitters released by the presynaptic cell. The binding of neurotransmitters can either excite the neuron, making it more likely to fire an action potential, or inhibit the neuron, making it less likely to fire.

Postsynaptic cell functions

• Signal Reception

  The primary function of the postsynaptic cell is to receive signals from the presynaptic cell. At chemical synapses, this occurs through the binding of neurotransmitters to receptors on the postsynaptic membrane.

• Signal Integration

  A postsynaptic neuron integrates signals from multiple presynaptic neurons, affecting whether it fires an action potential. This integration process is crucial for the complex information processing that underlies brain function.

• Synaptic Plasticity

  Changes in the strength of the synapse, known as synaptic plasticity, can involve postsynaptic receptor changes, presynaptic transmitter release, or both. This process, which can be influenced by the frequency and intensity of presynaptic signals, is thought to underlie learning and memory.

Postsynaptic Cell and Neurological Disorders

Dysfunction in the postsynaptic cell can contribute to a variety of neurological and psychiatric disorders. Changes in postsynaptic receptors and signaling are studied in conditions such as depression, schizophrenia, and Alzheimer's disease, but these complex disorders are not explained by a single receptor change. Studying these signals can help investigate disease mechanisms, but a receptor finding alone does not establish an effective treatment.

Sources and further reading

Chemical synapses; Okabe on postsynaptic density; presynaptic plasticity review.