Cerebellar basket cells inhibit postsynaptic Purkinje cells in a rapid and precise manner. To study the transmitter release mechanism of rapid inhibition, the kinetics of synaptic vesicle pool transitions and the intracellular Ca-dependence of transmitter release were measured at the basket cell synapse by directly stimulating transmitter release with caged Ca. While the transmitter release mechanism is essentially the same as the one at the excitatory synapses, synaptic vesicle replenishment is found to be driven by both residual and local Ca with requirement of unusually high Ca levels for triggering the process. This feature is different from the excitatory synapses, where only submicromolar Ca is required. Under physiological conditions, precise inhibition is not only mediated by the transmitter release mechanism, but also by the intrinsic firing properties, and the inputs from other neurons. We show that the inputs from parallel fiber have an important role in rapid and precise inhibition.