ISSN:
1432-0827
Keywords:
Osteoblast
;
Ion channels
;
Stretchactivation
;
Mechanical loading
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
,
Physics
Notes:
Abstract G292 osteoblastic cells were cultured in dishes made with a flexible base of polytetrafluoroethylene (PTFE) and stretched (∼1% strain level) continuously for 48 hours. Patch-clamp recording techniques were then used to monitor single channel currents of mechanosensitive ion channels in these cells. To stimulate mechanosensitive channels, we applied suction to the membrane, expressed as -cm Hg, directly through the patch pipette. GigaOhm seals were obtained on a total of 33 osteoblasts that contained a high-conductance (∼180 pS) mechanosensitive channel, all in the cell attached configuration. Of these, 18 were obtained from cells that had been stretched for either 1 (n=6), 24 (n=4), or 48 (n=8) hours, and 15 were obtained in control (nonstretched) cells at either 1 (n=2), 24 (n=5), or 48 (n=8) hours. For unstrained cells, applied pressures ranging from-1 to-5 cm Hg increased the probability of channel opening (Popen) from 0.05±0.01 (mean+SEM) to 0.12±0.07. By constrast, for the same values of applied pressure in stretched cells, Popen ranged from 0.06±0.01 to 0.49±0.15. Our results suggest that intrinsic properties of mechanosensitive ion channels in the G292 osteoblastic cell may be modulated by continous mechanical loading of the cell itself.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00369218
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