title: Insulin-secreting INS-1E cells express functional TRPV1 channels.
abstract: We have studied whether functional TRPV1 channels exist in the INS-1E cells, a cell type used as a model for β-cells, and in primary β-cells from rat and human. The effects of the TRPV1 agonists capsaicin and AM404 on the intracellular free Ca (2+) concentration ([Ca (2+)]i) in the INS-1E cells were studied by fura-2 based microfluorometry. Capsaicin increased [Ca (2+)]i in a concentration-dependent manner, and the [Ca (2+)]i increase was dependent on extracellular Ca (2+). AM404 also increased [Ca (2+)]i in the INS-1E cells. Capsazepine, a specific antagonist of TRPV1, completely blocked the capsaicin- and AM404-induced [Ca (2+)]i increases. Capsaicin did not increase [Ca (2+)]i in the primary β-cells from rat and human. Whole cell patch clamp configuration was used to record currents across the plasma membrane in the INS-1E cells. Capsaicin elicited inward currents that were inhibited by capsazepine. Western blot analysis detected TRPV1 proteins in the INS-1E cells and the human islets. Immunohistochemistry was used to study the expression of TRPV1, but no TRPV1 protein immunoreactivity was detected in the human islet cells and the human insulinoma cells. We conclude that the INS-1E cells, but not the primary β-cells, express functional TRPV1 channels.
authors.affiliation: Department of Clinical Science and Education; Södersjukhuset; Karolinska Institutet; Stockholm, Sweden.
authors.forename: Amanda Jabin
authors.initials: AJ
authors.lastname: Fågelskiöld
authors.affiliation: Department of Clinical Science and Education; Södersjukhuset; Karolinska Institutet; Stockholm, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kannisto
authors.affiliation: Department of Clinical Science and Education; Södersjukhuset; Karolinska Institutet; Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Boström
authors.affiliation: Department of Clinical Science and Education; Södersjukhuset; Karolinska Institutet; Stockholm, Sweden.
authors.forename: Banina
authors.initials: B
authors.lastname: Hadrovic
authors.affiliation: Nanion Technologies GmbH; Munich, Germany.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Farre
authors.affiliation: Department of Clinical Science and Education; Södersjukhuset; Karolinska Institutet; Stockholm, Sweden.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Eweida
authors.affiliation: Department of Genetics and Pathology; the Rudbeck Laboratory; Uppsala University; Uppsala, Sweden.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Wester
authors.affiliation: Department of Clinical Science and Education; Södersjukhuset; Karolinska Institutet; Stockholm, Sweden; Internal Medicine; Uppsala University Hospital; Uppsala, Sweden.
authors.forename: Md Shahidul
authors.initials: MS
authors.lastname: Islam
mesh_terms: D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002211:Capsaicin / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000502:physiology*; D006801:Humans; D050417:Insulin-Secreting Cells / Q000737:chemistry / Q000378:metabolism*; D007340:Insulinoma; D018408:Patch-Clamp Techniques; D051381:Rats; D050916:TRPV Cation Channels / Q000032:analysis / Q000378:metabolism*
chemical_list: D001095:Arachidonic Acids; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C493922:Trpv1 protein, rat; C071423:capsazepine; D002211:Capsaicin; D002118:Calcium; C107594:N-(4-hydroxyphenyl)arachidonylamide