PMID- 10519135
OWN - NLM
STAT- MEDLINE
DCOM- 19991122
LR  - 20190726
IS  - 0031-6768 (Print)
IS  - 0031-6768 (Linking)
VI  - 438
IP  - 4
DP  - 1999 Sep
TI  - Molecular and functional characterization of the small Ca(2+)-regulated K+
      channel (rSK4) of colonic crypts.
PG  - 437-44
AB  - Colonic crypt cells possess basolateral Ca(2+)-regulated K+ channels which
      support Cl- secretion by providing the necessary driving force. The
      pharmacological characteristics of these channels were examined in Ussing chamber
      experiments of rat and rabbit colon mucosa by the use of blockers. The chromanol 
      293B, a blocker of KVLQT1 channels, and clotrimazole (CTZ), a blocker of small
      Ca(2+)-activated K+ channels, blocked stimulated Cl- secretion completely.
      Small-conductance Ca(2+)-activated K+ channels (SK) in excised basolateral
      patches of rat colonic crypts were inhibited concentration dependently by the
      imidazoles CTZ, NS004 and NS1619 and activated by 1-EBIO. These properties are
      similar to those of the known human SK channel (hSK4). hSK4-expressing Xenopus
      laevis oocytes showed ionomycin-activated and CTZ-inhibited K+ currents. When
      P2Y2 receptors were coexpressed these currents were also activated by ATP. The
      concentration/response curve was identical to that of rat SK channels. In human
      colonocytes (T84) exposed to hSK4 antisense probes, but not to sense probes,
      carbachol-induced K+ currents were attenuated. With RT-PCR an hSK4 could be
      demonstrated in human colon and in T84 colonocytes. By homology cloning the SK of
      the rat colon (rSK4) was identified. This protein has a high homology to hSK4 and
      mouse IK1. These data indicate that the Ca(2+)-activated and imidazole-inhibited 
      basolateral K+ current in the colon is caused by SK4 channels.
FAU - Warth, R
AU  - Warth R
AD  - Physiologisches Institut, Albert-Ludwigs-Universitat, Freiburg, Germany.
FAU - Hamm, K
AU  - Hamm K
FAU - Bleich, M
AU  - Bleich M
FAU - Kunzelmann, K
AU  - Kunzelmann K
FAU - von Hahn, T
AU  - von Hahn T
FAU - Schreiber, R
AU  - Schreiber R
FAU - Ullrich, E
AU  - Ullrich E
FAU - Mengel, M
AU  - Mengel M
FAU - Trautmann, N
AU  - Trautmann N
FAU - Kindle, P
AU  - Kindle P
FAU - Schwab, A
AU  - Schwab A
FAU - Greger, R
AU  - Greger R
LA  - eng
SI  - GENBANK/AJ133438
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Germany
TA  - Pflugers Arch
JT  - Pflugers Archiv : European journal of physiology
JID - 0154720
RN  - 0 (Chlorides)
RN  - 0 (Imidazoles)
RN  - 0 (Intermediate-Conductance Calcium-Activated Potassium Channels)
RN  - 0 (KCNN4 protein, human)
RN  - 0 (Kcnn4 protein, rat)
RN  - 0 (Potassium Channel Blockers)
RN  - 0 (Potassium Channels)
RN  - 0 (Potassium Channels, Calcium-Activated)
RN  - 0 (RNA, Messenger)
RN  - 8Y164V895Y (Carbachol)
RN  - G07GZ97H65 (Clotrimazole)
SB  - IM
MH  - Animals
MH  - Carbachol/pharmacology
MH  - Cell Line
MH  - Chlorides/metabolism
MH  - Clotrimazole/pharmacology
MH  - Colon/cytology/drug effects/*metabolism
MH  - Electric Conductivity
MH  - Humans
MH  - Imidazoles/pharmacology
MH  - Intermediate-Conductance Calcium-Activated Potassium Channels
MH  - Intestinal Mucosa/cytology/drug effects/metabolism
MH  - Oocytes/metabolism
MH  - Potassium Channel Blockers
MH  - Potassium Channels/*genetics/*metabolism
MH  - *Potassium Channels, Calcium-Activated
MH  - RNA, Messenger/metabolism
MH  - Rabbits
MH  - Rats
MH  - Xenopus laevis
EDAT- 1999/10/16 00:00
MHDA- 1999/10/16 00:01
CRDT- 1999/10/16 00:00
PHST- 1999/10/16 00:00 [pubmed]
PHST- 1999/10/16 00:01 [medline]
PHST- 1999/10/16 00:00 [entrez]
AID - 10.1007/s004249900059 [doi]
PST - ppublish
SO  - Pflugers Arch. 1999 Sep;438(4):437-44. doi: 10.1007/s004249900059.