The RRP functions through a well-coordinated process of vesicle docking, priming, and fusion. Upon an action potential reaching the presynaptic terminal, voltage-gated calcium channels open, allowing calcium ions to enter the cell. This influx of calcium triggers the fusion of the primed vesicles in the RRP with the plasma membrane, leading to the release of their contents into the synaptic cleft. This rapid release is essential for fast synaptic transmission.
