Voltage-gated K+ channels are important determinants of neuronal membrane e, Xenopus/Amphibian,citability. Moreover, differences in K+ channel e, Xenopus/Amphibian,pression patterns and densities contribute to the variations in action potential waveforms and repetitive firing patterns evident in different neuronal cell types. The Kv3.1 potassium channel is e, Xenopus/Amphibian,pressed at high levels in neurons that characteristically fire rapid trains of action potentials. Particularly high levels of this channel are found in neurons of the auditory brainstem. These neurons appear to participate in neural circuits that determine the intensity and timing of auditory stimuli and use this information to determine the location of sounds in space.