Difference Between Synapse and Synaptic Cleft

Synapse vs Synaptic Cleft

Nervous system is a collection of well organized cellular circuits that allow an animal to perform certain essential tasks for survival. These circuits are made up of specialized cells called neurons, which are needed to transmit electrical and chemical signals, process sensory inputs, initiate behavioral responses, and regulate the internal physiology of organisms. The process of communication between neurons is known as synaptic transmission. Synapses and synaptic cleft help to make links between neurons, thus enhance the transmission efficiency between cellular circuits.


Synapse is a specialized intercellular site where fast, highly localized transmission of chemical and electrical signals can occur. Although the vast majority of synapses in the mammalian brain are chemical, synaptic transmission can be chemical or electrical. At chemical synapses, neurotransmitter molecules are released from a pre-synaptic terminal into a synaptic cleft. These molecules then diffuse and bind to recognition sites on target receptors of post synaptic membrane. Chemical synaptic transmission is fast, site- specific, and highly plastic.

At electrical synapses, ionotropic transmembrane channels on the plasma membrane allow ions and small molecules like ATP, Ca2+, and IP3 to cross between neurons. Morphologically, synaptic junctions resemble tight junctions with regular plasma membranes that are coated intercellular electrons. However, synapses differ from other junctions in that they are highly polarized. The three characteristic features of central synapses are pre-synaptic nerve terminals containing neurotransmitter- filled vesicles, post-synaptic membrane specializations containing clustered neurotransmitter receptors, and synaptic cleft.

Synaptic Cleft

The synaptic cleft is narrow extracellular gap (about 20 to 50 nm) that separates the pre and post synaptic membranes. As a central component of synapse, synaptic cleft performs both mechanical and signaling functions. Mechanical functions are to stabilize the parallel orientations of the pre and post-synaptic plasma membranes, connect these membranes to each other at a uniform distance, and coordinate their relative positions. Synaptic cleft is the space in which the neurotransmitters act. It also mediates non-transmitter signals between the pre-and post synaptic specializations.

What is the difference between Synapse and Synaptic Cleft?

• Synapse is the specialized site between two neurons, whereas synaptic cleft is referred to the narrow gap between post and pre synaptic membranes.

• Synapse has three component including pre-synaptic terminal, post-synaptic terminal, and synaptic cleft.

• Synaptic cleft is a component of synapse.