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Department of Molecular Physiology
Our interests
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olfaction
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Calcium - activated chloride channels |
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The Calcium-activated chloride channels open when the Ca
concentration in the cilia rises during odor detection. How much Ca does
this channel need to open? This can be investigated by excising membrane
patches from the ciliary knobs of OSNs and exposing the former internal
side of the membrane to a series of solutions with different Ca
concentrations. Plotting the resulting current against the Ca
concentration yields a dose-response curve for the activation of these
channels. This analysis shows that the channels needs about 1 µM Ca to
open.
Our studies of these channels have shown that the density of Cl channels
is about 8-fold higher than that of CNG channels in the ciliary
membrane, that a distance of roughly 120 nm separates each Cl channel
from the next CNG channel, and that several CNG channels, in concert,
drive the activity of each Cl channel. This functional coupling of two
distinct types of ion channels enables low-noise amplification of the
receptor current in OSNs
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