Mechanosensitive properties of BK channels from embryonic rat neuroepithelium.
The mechanosensitive properties of large-conductance Ca2+-activated K+ (BK) channels from embryonic rat neuroepithelium were investigated with the cell-attached and inside-out configurations of the patch-clamp technique. The channels were activated in both recording configurations by negative pressures applied to the patch electrode, but reversal of the effect was total and immediate in inside-out patches whereas it was incomplete and delayed in on-cell patches. This mechanosensitivity was not mediated by Ca2+ ions or fatty acids, suggesting that it is an intrinsic property of these channels. Cytochalasin B did not affect mechanosensitivity in on-cell patches but increased it in inside-out patches. Kinetic studies showed that stretch increased the mean open time of the channels and decreased the slowest time constant of their closed-time distributions. The present as well as previous results suggest complex interactions between embryonic BK channels and their membranous and submembranous environment.
Mienville
J
J
Laboratory of Neurophysiology, LNP, NINDS, NIH, Building 36, Room 2C02 36 Convent Dr MSC 4066 Bethesda MD 20892-4066, USA.
Barker
J L
JL
Lange
G D
GD
D000818:Animals; D004848:Epithelium / Q000196:embryology / Q000502:physiology; D005333:Fetus / Q000502:physiology; D009420:Nervous System / Q000196:embryology; D009424:Nervous System Physiological Phenomena; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D013314:Stress, Mechanical
D015221:Potassium Channels