What leads to synaptic fatigue?

Synaptic fatigue occurs when there is an excessive release of neurotransmitters, which surpasses the rate at which these neurotransmitters can be broken down or recycled. In a typical neurotransmission process, when an action potential reaches the presynaptic terminal, it triggers the release of neurotransmitters into the synaptic cleft. If this release is too high or sustained over time, the presynaptic terminal may not be able to adequately manage the high levels of neurotransmitters generated, leading to a depletion of available neurotransmitters to sustain further signaling. Consequently, this can impair synaptic transmission, resulting in reduced efficacy of signal transmission and a diminished response in the postsynaptic neuron.

Understanding this mechanism is crucial in the context of synaptic functioning, as it highlights the delicate balance needed between neurotransmitter release, degradation, and recycling to maintain proper synaptic health and function.