Possible involvement of mechanosensitive Ca2+ channels of plasma membrane in mechanoperception in Chara.
When an internodal cell of Chara corallina was stimulated with a mechanical pulse of various amplitudes lasting for 0.1 s (mechanical stimulus), the cell generated a receptor potential, which was highly dependent not only on the strength of the stimulus but also on the extracellular Cl- concentration. Extracellular Ca2+ was indispensable for generating receptor potential, since removal of Ca2+ reversibly inhibited generation of the receptor potential. The cytoplasmic Ca2+ level transiently rose upon mechanical stimulation. The stronger the mechanical stimulus, the larger was the increase in the cytoplasmic level of Ca2+. It is proposed that the first step of receptor potential is an activation of mechanosensitive Ca2+ channels at the plasma membrane.
Kaneko
Toshiyuki
T
Graduate School of Science and Technology, Niigata University, Niigata, 950-2181 Japan.
Saito
Chiyuki
C
Shimmen
Teruo
T
Kikuyama
Munehiro
M
D015220:Calcium Channels / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D044784:Chara / Q000378:metabolism*; D040542:Mechanotransduction, Cellular; D008564:Membrane Potentials
D015220:Calcium Channels