{"created":"2023-06-20T13:21:02.568536+00:00","id":1137,"links":{},"metadata":{"_buckets":{"deposit":"95800ee4-d3f5-4fa5-ba16-8296cac97cb3"},"_deposit":{"created_by":1,"id":"1137","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"1137"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00001137","sets":["2:430:22"]},"author_link":["9428","9427","9426"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"DUTTA, Amal Kumar"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"アマル,  クーマー ダッタ"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2003-03-24"}]},"item_1_degree_grantor_5":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"総合研究大学院大学"}]}]},"item_1_degree_name_6":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"Mouse mammary C127 cells responded to hypotonic stimulation with activation of the volume-dependent ATP-conductive large-conductance (VDACL) anion channel and massive release of ATP.  Arachidonic acid down-regulated both VDACL currents and swelling-induced ATP release in the physiological concentration range with the Kd value of 4-6 μM.  The former effect observed in the whole-cell or excised patch-clamp mode was more prominent than the latter effect observed in intact cells.  The arachidonate effects were direct and not mediated by downstream metabolic products as evidenced by their insensitivity to inhibitors of arachidonate-metabolizing oxygenases and by the mimicking effect of cis-unsaturated fatty acids, which are not substrates for oxygenases.  A membrane-impermeable arachidonate analog, arachidonyl coenzyme A, was effective only when applied from the cytosolic side of membrane patches, suggesting that the binding site is localized intracellularly.  Non-charged arachidonate analogs as well as trans-unsaturated and saturated fatty acids had no effect on VDACL currents and ATP release indicating the importance of arachidonate's negative charges and a specific hydrocarbon chain conformation in the inhibitory effect.  VDACL anion channels were inhibited by arachidonic acid in two different ways:  channel shutdown (Kd of 4-5 μM) and reduced unitary conductance (Kd of 13-14 μM) without affecting voltage dependence of open probability.  ATP4-conducting inward currents measured in the presence of 100 mM ATP in the bath were also reversibly inhibited by arachidonic acid.  Thus he concludes that swelling-induced ATP release and its putative pathway, the VDACL anion channel are under a negative control by intracellular arachidonic acid signaling in mammary C127 cells.<br />  From neonatal rat cardiomyocytes in primary culture ATP was found to be massively released by hypotonic stress or chemical ischemia produced by application of metabolic inhibitors.  The release of ATP both in ischemic and hypotonic conditions was time-dependent and displayed an initial peak followed by a sustained phase as detected by a luciferine/luciferase ATP assay method.  The local concentration of ATP near the cell surface during hypotonic or ischemic stimulation was found to exceed micromolar levels estimated by a biosensor technique.  In the cell-attached configuration of patch-clamp, either hypotonic or ischemic stimulation activated an anion channel of large conductance after a lag period of 5-8 min.  The currents displayed voltage- and time-dependent inactivation at potentials larger than ±20 mV.  The single-channel conductance was app. 400 pS, with a linear current-voltage relationship.  The channel was anion-selective and exhibited ATP permeability with P ATP /P Cl of ～0.1.  The maxi-Cl channel activity and swelling-induced ATP release were both inhibited by NPPB, SITS. Gd3+ and arachidonic acid, but not by glibenclamide.  The biophysical as well as phramacological profiles of large-conductance channels in cardiomyocytes were essentially identical to those of VDACL channel in C127 cells.<br />  Both massive release of ATP and activation of large-conductance anion channel were observed also when cardiomyocytes were subjected to hypoxia.  In this experimental condition, in addition to the full-amplitude of VDACL unitary current, cell-attached patches contained single-channel events with unitary conductance of app. half of large-conductance channel size (～250-200 pS).  Voltage dependency, anion selectivity and ATP permeability of this half-sized channel event were similar to these parameters of full-sized VDACL channel event.  He concludes that this smaller amplitude represents a sub-state of fully open VDACL channel.  The sub-state channel activity was predominant in the cell-attached patch mode (especially in hypoxic conditions) than in the inside-out mode.  Thus, it is concluded that ATP is released from cardiomyocytes in response to pathophysiological situations, like cell swelling and ischemia or hypoxia, and the VDACL channel serves as the conductive pathway for ATP release from cardiomyocytes.","subitem_description_type":"Other"}]},"item_1_description_18":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_1_description_7":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"総研大甲第706号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"生命科学研究科"}]},"item_1_select_9":{"attribute_name":"専攻","attribute_value_mlt":[{"subitem_select_item":"20 生理科学専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2002"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"DUTTA, Amal Kumar","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲706_要旨.pdf","filesize":[{"value":"262.5 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨 / Abstract, Screening Result","url":"https://ir.soken.ac.jp/record/1137/files/甲706_要旨.pdf"},"version_id":"c6443ae5-1dc2-4ca0-b0a9-5b441e90c254"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲706_本文.pdf","filesize":[{"value":"3.0 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文","url":"https://ir.soken.ac.jp/record/1137/files/甲706_本文.pdf"},"version_id":"646b93bf-e2b1-450b-af63-fd6ea3e5d07d"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"ATP-conductive channel and ATP release:  Regulation by arachidonic acid and activation in ischemic conditions","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"ATP-conductive channel and ATP release:  Regulation by arachidonic acid and activation in ischemic conditions"},{"subitem_title":"ATP-conductive channel and ATP release:  Regulation by arachidonic acid and activation in ischemic conditions","subitem_title_language":"en"}]},"item_type_id":"1","owner":"1","path":["22"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-02-22"},"publish_date":"2010-02-22","publish_status":"0","recid":"1137","relation_version_is_last":true,"title":["ATP-conductive channel and ATP release:  Regulation by arachidonic acid and activation in ischemic conditions"],"weko_creator_id":"1","weko_shared_id":1},"updated":"2023-06-20T14:47:10.315843+00:00"}