title: Modulation of staurosporine-activated volume-sensitive outwardly rectifying Cl⁻ channel by PI3K/Akt in cardiomyocytes.
abstract: Chloride (Cl⁻) channels participate in the regulation of cardiac function in response to stress although the underlying regulatory mechanism remains poorly understood. This study was designed to examine the impact of the pro-apoptotic stimulus staurosporine (STS) on the volume-sensitive outwardly rectifying Cl⁻ current (I(Cl,Vol)) in cardiomyocytes and possible regulatory mechanism involved with a focus on phosphatidylinositol-3 kinase (PI3K)/Akt. Primary cultured rat neonatal cardiomyocytes were subjected to hypotonic and isotonic environment in the presence or absence of STS prior to whole-cell voltage-clamp evaluation of Cl⁻ current. Whole-cell recordings revealed that STS activated an outwardly rectifying Cl⁻ current with phenotypic properties reminiscent of I(Cl,Vol). These currents were outwardly rectifying with a time-dependent inactivation at positive potentials and were sensitive to 4,4'-diisothiocya-natostilbene- 2,2'- disulfonicacid (DIDS), a non-selective Cl⁻ channel blocker, and 4-(2-butyl-6,7-dichlor-2-cyclopentyl-indan-1-on-5-yl)oxybutyric acid (DCPIB), a selective VSOR Cl⁻ channel blocker. DIDS and DCPIB inhibited I(Cl,Vol) by 92.6% ± 7.3% and 78.4% ± 5.5%, respectively. Our data further revealed that the PI3K inhibitor LY294002 facilitated the current with the peak amplitude of 19.54 ± 2.70 pA/pF. To the contrary, insulin partially inhibited the current amplitude with the peak current amplitude of 15.4 ± 2.13 pA/pF. Taken together, our data depicted staurosporine is capable of activating I(Cl,Vol) channel in cardiomyocytes via possibly a PI3K/Akt-dependent mechanism.
authors: Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors: Yan
authors: Y
authors: Liu
authors: Bo
authors: B
authors: Wang
authors: Wei-Wei
authors: WW
authors: Zhang
authors: Jia-Ni
authors: JN
authors: Liu
authors: Ming-Zhi
authors: MZ
authors: Shen
authors: Ming-Ge
authors: MG
authors: Ding
authors: Xiao-Ming
authors: XM
authors: Wang
authors: Jun
authors: J
authors: Ren
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D065101:Chloride Channel Agonists; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007038:Hypotonic Solutions; D007328:Insulin / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D049990:Membrane Transport Modulators / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D058539:Phosphatidylinositol 3-Kinase / Q000737:chemistry / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D019311:Staurosporine / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D065101:Chloride Channel Agonists; D018118:Chloride Channels; D004791:Enzyme Inhibitors; D007004:Hypoglycemic Agents; D007038:Hypotonic Solutions; D007328:Insulin; D049990:Membrane Transport Modulators; D000081082:Phosphoinositide-3 Kinase Inhibitors; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D019311:Staurosporine