MECHANOSENSITIVE CATION CHANNELS OF LEECH NEURONS

Mechanosensitive ion channels are expressed in the central nervous system of the medicinal leech. The plasma membranes of neurons whose primary function is not sensory contain stretch-activated cation channels in relatively high density. Different stimuli, associated with membrane deformation, such as perfusion with hypotonic solutions or pressure pulses applied to the patch pipette, increase the channel's open probability. These cation channels contribute to macroscopic elevations of intracellular free calcium concentration produced by cell mechanical stimulation. Leech cation channels exhibit two activity modes differing both in kinetics and in conductance. In regenerating neurons one of these modes, characterized by long mean channel open time and high mechanosusceptibility, is preferentially expressed. Gentamicin, a voltage-dependent blocker of these channels, affects the neurite growth in culture. A possible role of mechanosensitive cation channels in the processes of neurite growth is discussed.