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Anorexic effect of K+ channel blockade in mesenteric arterial smooth muscle and intestinal epithelial cells.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Platoshyn, Oleksandr Yu, Yongxin Sweeney, Meghan Miriel, Victor A. Krick, Stefanie Lapp, Bethany R. Yuan, Jason X-J |
| Copyright Year | 2001 |
| Abstract | Activity of voltage-gated K+ (Kv) channels controls membrane potential (E(m)). Membrane depolarization due to blockade of K+ channels in mesenteric artery smooth muscle cells (MASMC) should increase cytoplasmic free Ca2+ concentration ([Ca2+]cyt) and cause vasoconstriction, which may subsequently reduce the mesenteric blood flow and inhibit the transportation of absorbed nutrients to the liver and adipose tissue. In this study, we characterized and compared the electrophysiological properties and molecular identities of Kv channels and examined the role of Kv channel function in regulating E(m) in MASMC and intestinal epithelial cells (IEC). MASMC and IEC functionally expressed multiple Kv channel alpha- and beta-subunits (Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5, Kv2.1, Kv4.3, and Kv9.3, as well as Kvbeta1.1, Kvbeta2.1, and Kvbeta3), but only MASMC expressed voltage-dependent Ca2+ channels. The current density and the activation and inactivation kinetics of whole cell Kv currents were similar in MASMC and IEC. Extracellular application of 4-aminopyridine (4-AP), a Kv-channel blocker, reduced whole cell Kv currents and caused E(m) depolarization in both MASMC and IEC. The 4-AP-induced E(m) depolarization increased [Ca2+]cyt in MASMC and caused mesenteric vasoconstriction. Furthermore, ingestion of 4-AP significantly reduced the weight gain in rats. These results suggest that MASMC and IEC express multiple Kv channel alpha- and beta-subunits. The function of these Kv channels plays an important role in controlling E(m). The membrane depolarization-mediated increase in [Ca2+]cyt in MASMC and mesenteric vasoconstriction may inhibit transportation of absorbed nutrients via mesenteric circulation and limit weight gain. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://jap.physiology.org/content/jap/91/5/2322.full.pdf |
| PubMed reference number | 11641377v1 |
| Volume Number | 91 |
| Issue Number | 5 |
| Journal | Journal of applied physiology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Adipose tissue Anorexia Artery Smooth Muscle Tissue Heparin, Low-Molecular-Weight Kinetics (discipline) Membrane Potentials Mesenteric Arteries Mesentery Muscle Cells Myocytes, Smooth Muscle Nutrients Potassium Sense of identity (observable entity) Smooth muscle (tissue) Splanchnic Circulation Vascular constriction (function) dalfampridine membrane depolarization |
| Content Type | Text |
| Resource Type | Article |
