Intracellular channels are located on the membranes of intracellular organelles and are involved in ion transfer, within the cytosolic compartments, in response to internal stimuli. Recently, various types of inositol 1,4,5-trisphosphate- and ryanodine-sensitive Ca(2+)-release channels, mitochondrial voltage-dependent anion channels, and a vesicular Cl- channel have been molecularly cloned and characterized, and their functional roles in the central nervous system are beginning to be clarified.