Biomedical Engineering Reference
In-Depth Information
Figure 16. Charge vs. time
t
curves following a potential step from -0.300 to
-0.720 V/SCE at a tBLM incorporating the HERG channel in 0.1 M KCl, both
before (
a
) and after addition (
b
) of 5 PM WAY. The inset shows the curve of the
charge
Q
against time t, obtained by subtracting curve (
b
) from curve (a), and the
corresponding curve of the current
I
against
t
; both
Q
and
I
are ascribable to the
HERG channel activation.
184
charge vs. time curve due exclusively to the opening of the HERG
channel was obtained, as shown by the inset of
Fig. 16
. The same
procedure was followed to obtain the corresponding current versus
time curve; this curve shows a monoexponential decay with time,
with a time constant in good agreement with that obtained by the
patch-clamp technique with conventional BLMs.
Sarcolipin (SLN) and phospholamban (PLN) are two small
membrane proteins that modulate the function of Ca-ATPase of
the sarcoplasmic reticulum. They were incorporated in a mercury-
supported DPTL/DPhyPC bilayer to verify whether these two pro-
teins may form ion-selective pores in biomembranes.
194-196
SLN
inhibits the Ca-ATPase activity at low Ca
2+
concentrations. How-
ever, it is also reported to increase the level of Ca
2+
accumulation
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