Kir6.1 channels
| Channel name | Kir6.1 |
| Description | ATP-sensitive potassium channel Kir6.1 subunit, NDP-dependent potassium channel Kir6.1 subunit |
| Other names | uKATP-1 |
| Molecular information | Human (KCNJ8): 424aa, Locus ID: 3764, GenBank: D50315, NM_004982, PMID: 8595887,1 chr. 12p11.23 |
| Rat (Kcnj8): 424aa, Locus ID: 25472, GenBank: D42145, NM_017099, PMID: 8595887,2 chr. 4q44 | |
| Mouse (Kcnj8): 424aa, Locus ID: 16523, GenBank: D88159, NM_008428, PMID: 9130167,3 chr. 6G3; 6, 70.0 centimorgans | |
| Associated subunits | SUR1, SUR2A, and SUR2B in reconstituted systems; SUR2B in native tissues |
| Functional assays | Voltage-clamp |
| Current | IK(NDP) |
| Conductance | 33 to 40pS (in 140 mM K+) |
| Ion selectivity | K+ |
| Activation | Nucleoside diphosphates |
| Inactivation | Not established |
| Activators | NDP, diazoxide, pinacidil, nicorandil (for associated SUR subunits) |
| Gating inhibitors | None |
| Blockers | Glibenclamide (for associated SUR subunits) |
| Radioligands | [3H]Glibenclamide (for associated SUR subunits) |
| Channel distribution | Vascular smooth muscle |
| Physiological functions | Regulation of vascular smooth muscle tone |
| Mutations and pathophysiology | Mouse lacking Kir6.1 is a model of vasospastic (Prinzmetal) angina4 |
| Pharmacological significance | SUR2B is a target for antihypertensive agents and coronary vasodilators |
aa, amino acids; chr., chromosome; NDP, nucleotide diphosphate; SUR, sulfonylurea receptor.
↵1. Inagaki N, Inazawa J, and Seino S (1995) cDNA sequence, gene, structure and chromosomal localization of the human ATP-sensitive potassium channel u-K(ATP)-1 gene (KCNJ8). Genomics 30:102-104
↵2. Inagaki N, Tsuura Y, Namba N, Masuda K, Gonoi T, Horie M, Seino Y, Mizuta M, and Seino S (1995) Cloning and functional characterization of a novel ATP-sensitive potassium channel ubiquitously expressed in rat tissues including pancreatic islets pituitary skeletal muscle and heart. J Biol Chem 270:5691-5694
↵3. Yamada M, Isomoto S, Matsumoto S, Kondo C, Shindo T, Horio Y, and Kurachi Y (1997) Sulphonylurea receptor 2B and Kir 6.1 form a sulphonyl urea-sensitive but ATP insensitive K+ channel. J Physiol 499:715-720
↵4. Miki T, Suzuki M, Shibasaki T, Uemura H, Sato T, Yamaguchi K, Koseki H, Iwanaga T, Nakaya H, and Seino S (2002) Mouse model of Prinzmetal angina by disruption of the inward rectifier Kir6.1. Nat Med 8: 466-472