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ATP‐sensitive potassium channels in capillaries isolated from guinea‐pig heart
| Content Provider | Scilit |
|---|---|
| Author | Schnitzler, Michael Mederos Y. Derst, Christian Daut, Jürgen Preisig‐Müller, Regina |
| Copyright Year | 2000 |
| Description | Journal: The Journal of physiology The full-length cDNAs of two different alpha-subunits (Kir6.1 and Kir6.2) and partial cDNAs of three different beta-subunits (SUR1, SUR2A and SUR2B) of ATP-sensitive potassium (KATP) channels of the guinea-pig (gp) were obtained by screening a cDNA library from the ventricle of guinea-pig heart. Cell-specific reverse-transcriptase PCR with gene-specific intron-spanning primers showed that gpKir6.1, gpKir6.2 and gpSUR2B were expressed in a purified fraction of capillary endothelial cells. In cardiomyocytes, gpKir6.1, gpKir6.2, gpSUR1 and gpSUR2A were detected. Patch-clamp measurements were carried out in isolated capillary fragments consisting of 3-15 endothelial cells. The membrane capacitance measured in the whole-cell mode was 19.9 +/- 1.0 pF and was independent of the length of the capillary fragment, which suggests that the endothelial cells were not electrically coupled under our experimental conditions. The perforated-patch technique was used to measure the steady-state current-voltage relation of capillary endothelial cells. Application of K+ channel openers (rilmakalim or diazoxide) or metabolic inhibition (250 microM 2,4-dinitrophenol plus 10 mM deoxyglucose) induced a current that reversed near the calculated K+ equilibrium potential. Rilmakalim (1 microM), diazoxide (300 microM) and metabolic inhibition increased the slope conductance measured at -55 mV by a factor of 9.0 (+/-1.8), 2.5 (+/-0.2) and 3.9 (+/-1.7), respectively. The effects were reversed by glibenclamide (1 microM). Our results suggest that capillary endothelial cells from guinea-pig heart express KATP channels composed of SUR2B and Kir6.1 and/or Kir6.2 subunits. The hyperpolarization elicited by the opening of KATP channels may lead to an increase in free cytosolic Ca2+, and thus modulate the synthesis of NO and the permeability of the capillary wall. |
| Related Links | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2269954/pdf |
| Ending Page | 317 |
| Page Count | 11 |
| Starting Page | 307 |
| ISSN | 00223751 |
| e-ISSN | 14697793 |
| DOI | 10.1111/j.1469-7793.2000.t01-1-00307.x |
| Journal | The Journal of physiology |
| Issue Number | 2 |
| Volume Number | 525 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 2000-06-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: The Journal of physiology Endothelial Cells |
| Content Type | Text |
| Resource Type | Article |
| Subject | Physiology Sports Science |
