Biomedical Engineering Reference
In-Depth Information
O
O
OH
17, Indanylooxyacetic acid
4.5 Other Cl
Transporting Systems and Their Blockers
In addition to the above important classes of Cl
channels and their blockers
described in the preceding sections, there are some other systems by which chloride
ions can be transported, for example, Na
2+
/2Cl
/K
+
carrier and apolar cells. A brief
description of these two and their blockers are given below.
4.5.1 Na
2+
/2Cl
/K
+
Carrier
Na
2+
/2Cl
/K
+
carrier was detected by Geck et al. [
189
] to be another Cl
transport
system. This system is found in many polar and apolar cells [
166
,
190
]. It was so far
believed to be only a primary pump, sensitive to furosemide (18)-like substances,
but now it has been found to also act as a secondary active chloride carrier. Thus,
the chloride transport can be blocked by all furosemide-like substances, for exam-
ple, furosemide (18), piretanide (19), triflocine (20), and torasemide (21), which
can interact with Na
2+
/2Cl
/K
+
carrier in epithelial cells. This carrier acts as
transepithelial transporter of NaCl, and is found together with Cl
channels on
the opposite cell membranes [
191
].
O
O
HN
HO
Cl
S
O
O
NH
2
18, Furosemide
O
O
H
2
N
S
OH
O
O
N
