The inhibitor of volume‐regulated anion channels DCPIB activates TREK potassium channels in cultured astrocytes. (20th February 2013)

• Record Type: Journal Article
• Authors: Minieri, L; Pivonkova, H; Caprini, M; Harantova, L; Anderova, M; Ferroni, S
• Is Part Of: British journal of pharmacology. Volume 168:Number 5(2013:Mar.)
• Page Start: 1240
• Page End: 1254
• Publication Date: 2013-02-20
• Subjects: Pharmacology -- Periodicals; Chemotherapy -- Periodicals; Drug Therapy -- Periodicals; Pharmacology -- Periodicals; 615.1
• DOI: 10.1111/bph.12011
• Languages: English
• ISSNs: 0007-1188

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="bph12011-sec-0001" sec-type="section"> <title>Background and Purpose</title> <p>The ethacrynic acid derivative, 4‐(2‐butyl‐6, 7‐dichlor‐2‐cyclopentylindan‐1‐on‐5‐yl) oxobutyric acid (DCPIB) is considered to be a specific and potent inhibitor of volume‐regulated anion channels (VRACs). In the CNS, DCPIB was shown to be neuroprotective through mechanisms principally associated to its action on VRACs. We hypothesized that DCPIB could also regulate the activity of other astroglial channels involved in cell volume homeostasis.</p> </sec> <sec id="bph12011-sec-0002" sec-type="section"> <title>Experimental Approach</title> <p>Experiments were performed in rat cortical astrocytes in primary culture and in hippocampal astrocytes <italic>in situ</italic>. The effect of DCPIB was evaluated by patch‐clamp electrophysiology and immunocytochemical techniques. Results were verified by comparative analysis with recombinant channels expressed in COS‐7 cells.</p> </sec> <sec id="bph12011-sec-0003" sec-type="section"> <title>Key Results</title> <p>In cultured astrocytes, DCPIB promoted the activation of a K<sup>+</sup> conductance mediated by two‐pore‐domain K<sup>+</sup> (K<sub>2P</sub>) channels. The DCPIB effect occluded that of arachidonic acid, which activates K<sub>2P</sub> channels K<sub>2P</sub> 2.1 (TREK‐1) and K<sub>2P</sub> 10.1 (TREK‐2) in cultured astrocytes. Immunocytochemical analysis suggests that cultured astrocytes express K<sub>2P</sub> 2.1 and K<sub>2P</sub> 10.1 proteins. Moreover, DCPIB opened recombinant K<sub>2P</sub> 2.1 and K<sub>2P</sub> 10.1 expressed in heterologous system. In brain slices, DCPIB did not augment the large background K<sup>+</sup> conductance in hippocampal astrocytes, but caused an increment in basal K<sup>+</sup> current of neurons.</p> </sec> <sec id="bph12011-sec-0004" sec-type="section"> <title>Conclusion and Implications</title> <p>Our results indicate that the neuroprotective effect of DCPIB could be due, at least in part, to activation of TREK channels. DCPIB could be used as template to build new pharmacological tools able to increase background K<sup>+</sup> conductance in astroglia and neuronal cells.</p> </sec> </abstract>