MULTIMODAL ACTIVATION AND REGULATION OF NEURONAL MECHANOSENSITIVE CATION CHANNELS

Recent findings show that mechanosensitive cation channels are expressed in the central nervous system. These molecules can be found not only, as expected, in mechanosensory cells but also in neurons not involved in sensory mechanotransduction. The expression of these channels in nonspecialized neurons is related to the need for cells to deal with general functions such as volume and electrolyte homeostasis as well as cell movement regulation. Since adhesion and advance of nerve growth cones are associated with changes in membrane tension and with oscillations of intracellular calcium concentration, mechanosensitive cation channels may play critical roles in neurite growth. In keeping with this, elementary mechanosensitive cation currents can be recorded from membranes of neuronal growth cones. Large conductance mechanosensitive cation channels have been investigated in central neurons of the leech. A multimodal activation, by membrane potential, intracellular calcium and pH, as well as a powerful modulation by adenosine nucleotides have been recently established. These features are discussed as possible mechanisms enabling these channels to contribute to neurite remodeling.