S-Space College of Medicine/School of Medicine (의과대학/대학원) Otorhinolaryngology (이비인후과학전공) Journal Papers (저널논문_이비인후과학전공)
Reactive blue 2, an antagonist of rat P2Y4, increases K+ secretion in rat cochlea strial marginal cells
- Lee, Jun Ho; Heo, Jeong-Hwa; Chang, Sun O; Kim, Chong-Sun; Oh, Seung-Ha
- Issue Date
- Hear Res. 2006 Sep;219(1-2):66-73. Epub 2006 Jul 12.
- 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid/pharmacology; Adenosine Triphosphate/analogs & derivatives/pharmacology; Animals; Dose-Response Relationship, Drug; Electrophysiology; Enzyme Inhibitors/*pharmacology; Ion Transport/drug effects/physiology; Perilymph/metabolism; Potassium/*metabolism; Rats; Receptors, Purinergic P2/agonists/*antagonists & inhibitors; Sodium-Potassium-Exchanging ATPase/metabolism; Stria Vascularis/cytology/*drug effects/secretion; Suramin/pharmacology; Triazines/*pharmacology; Uridine Triphosphate/pharmacology; Vibration
- Extracellular ATP decreases K+ secretion in strial marginal cells via apical P2Y4 receptors. We investigated the effect of reactive blue 2 (RB-2), an antagonist of rat P2Y4, on rat strial marginal cells using a voltage-sensitive vibrating probe. The application of RB-2 increased K+ secretion in a dose-dependent manner, and this increase was characterized as a peak followed by a partial relaxation to a steady-state. Moreover, this response was similar to that caused by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS). Suramin had no similar effect, except at high concentration. Thus, we tested the effects of these chemicals on P2Y4 receptors in strial marginal cells. Both RB-2 and DIDS had antagonistic activities at P2Y4, and the antagonist potency at P2Y4 paralleled the potency of K+ secretion. Interestingly, 2'- and 3'-O-(4-benzoyl-benzoyl)adenosine 5'-triphosphate (BzATP) exhibited an agonistic effect at P2Y4 receptor, which was blocked by RB-2, but not by pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). Based on these results, we speculate that direct and/or indirect inhibitory mechanisms between P2Y4 and KENQ1/KCNE1 K+ channels exist in strial marginal cell.
- 0378-5955 (Print)
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