Neurons communicate with each other either through electrical synapses formed by gap junctions, or by the synaptic release of neurotransmitters. Release of neurotransmitter into the synaptic cleft is occurs when loaded synaptic vesicles fuse to the plasma membrane (exocytosis). Neurons have a compensatory process that retrieves fused vesicle membrane from the active zone (endocytosis), maintaining membrane homeostasis. Presynaptic capacitance (Cm) measurements can directly test exo- and endocytosis mechanisms with microsecond temporal resolution without interference from saturation or desensitization of postsynaptic receptors. The biggest limitation of Cm measurements is that they require high frequency stimulation, which has limited this technique to cells with simple morphology or patchable large terminals. Developments in this field indicate that neurons and synaptic terminals with more complicated morphology can be studied using this technique. The focus of this study is on a retinal interneuron, the AII amacrine cell (AII-AC), that is the only inhibitory interneuron to be studied using Cm measurements to date.