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Pancreatic two P domain K + channels TALK‐1 and TALK‐2 are activated by nitric oxide and reactive oxygen species
Author(s) -
Duprat F.,
Girard C.,
Jarretou G.,
Lazdunski M.
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2004.071266
Subject(s) - nitric oxide , chemistry , xanthine oxidase , reactive oxygen species , pancreas , dithiothreitol , xanthine , superoxide , medicine , endocrinology , biochemistry , biology , enzyme , organic chemistry
This study firstly shows with in situ hybridization on human pancreas that TALK‐1 and TALK‐2, two members of the 2P domain potassium channel (K 2P ) family, are highly and specifically expressed in the exocrine pancreas and absent in Langherans islets. On the contrary, expression of TASK‐2 in mouse pancreas is found both in the exocrine pancreas and in the Langherans islets. This study also shows that TALK‐1 and TALK‐2 channels, expressed in Xenopus oocytes, are strongly and specifically activated by nitric oxide (obtained with a mixture of sodium nitroprussate (SNP) and dithiothreitol (DTT)), superoxide anion (obtained with xanthine and xanthine oxidase) and singlet oxygen (obtained upon photoactivation of rose bengal, and with chloramine T). Other nitric oxide and reactive oxygen species (NOS and ROS) donors, as well as reducing conditions were found to be ineffective on TALK‐1, TALK‐2 and TASK‐2 (sin‐1, angeli's salt, SNP alone, tBHP, H 2 O 2 , and DTT). These results suggest that, in the exocrine pancreas, specific members of the NOS and ROS families could act as endogenous modulators of TALK channels with a role in normal secretion as well as in disease states such as acute pancreatitis and apoptosis.