| Id |
Subject |
Object |
Predicate |
Lexical cue |
| T1 |
0-52 |
Sentence |
denotes |
Ca2+ dependence of the Ca2+-selective TRPV6 channel. |
| T2 |
53-224 |
Sentence |
denotes |
Microfluorimetry and patch-clamp experiments were performed on TRPV6-expressing HEK cells to determine whether this Ca(2+)-sensing Ca(2+) channel is constitutively active. |
| T3 |
225-435 |
Sentence |
denotes |
Intact cells loaded with fura-2 had an elevated intracellular free Ca(2+) concentration ([Ca(2+)](i)), which decreased to the same level such as in non-transfected cells if external Ca(2+) was chelated by EGTA. |
| T4 |
436-761 |
Sentence |
denotes |
Whole cell recordings from non-transfected HEK cells and cells expressing human TRPV6 revealed the presence of a basal inward current in both types of cells when the internal solution contained 0.1 mm EGTA and 100 nm [Ca(2+)](i) or if the cytosolic Ca(2+) buffering remained undisturbed in perforated patch-clamp experiments. |
| T5 |
762-925 |
Sentence |
denotes |
If recombinantly expressed TRPV6 forms open channels, one would expect Ca(2+)-induced current inhibition, because TRPV6 is negatively regulated by internal Ca(2+). |
| T6 |
926-1130 |
Sentence |
denotes |
However, dialyzing solutions with high [Ca(2+)] such as 1 microm into TRPV6-expressing cells did not block the basal inward current, which was not different from the recordings from non-transfected cells. |
| T7 |
1131-1285 |
Sentence |
denotes |
In contrast, dialyzing 0.5 mm EGTA into TRPV6-expressing cells readily activated Ca(2+) inward currents, which were undetectable in non-transfected cells. |
| T8 |
1286-1491 |
Sentence |
denotes |
Interestingly, monovalent cations permeated the TRPV6 channels under conditions where no Ca(2+) permeation was detectable, indicating that divalent cations block TRPV6 channels from the extracellular side. |
| T9 |
1492-1787 |
Sentence |
denotes |
Like human TRPV6, the truncated human TRPV6(Delta695-725), which lacks the C-terminal domain required for Ca(2+)-calmodulin binding, does not form constitutive active channels, whereas the human TRPV6(D542A), carrying a point mutation in the presumed pore region, does not function as a channel. |
| T10 |
1788-1904 |
Sentence |
denotes |
In summary, no constitutive open TRPV6 channels were detected in patch-clamp experiments from transfected HEK cells. |
| T11 |
1905-2003 |
Sentence |
denotes |
However, channel activity is highly regulated by intracellular and extracellular divalent cations. |
