title: Hydrogen sulfide induces hyperpolarization and decreases the exocytosis of secretory granules of rat GH3 pituitary tumor cells.
abstract: The aim of the present study was to evaluate the effects of hydrogen sulfide (H2S) on the membrane potential, action potential discharge and exocytosis of secretory granules in neurosecretory pituitary tumor cells (GH3). The H2S donor - sodium hydrosulfide (NaHS) induced membrane hyperpolarization, followed by truncation of spontaneous electrical activity and decrease of the membrane resistance. The NaHS effect was dose-dependent with an EC50 of 152 μM (equals effective H2S of 16-19 μM). NaHS effects were not altered after inhibition of maxi conductance calcium-activated potassium (BK) channels by tetraethylammonium or paxilline, but were significantly reduced after inhibition or activation of ATP-dependent potassium channels (KATP) by glibenclamide or by diazoxide, respectively. In whole-cell recordings NaHS increased the amplitude of KATP currents, induced by hyperpolarizing pulses and subsequent application of glibenclamide decreased currents to control levels. Using the fluorescent dye FM 1-43 exocytosis of secretory granules was analyzed in basal and stimulated conditions (high K(+) external solution). Prior application of NaHS decreased the fluorescence of the cell membrane in both conditions which links with activation of KATP currents (basal secretion) and activation of KATP currents and BK-currents (stimulated exocytosis). We suggest that H2S induces hyperpolarization of GH3 cells by activation of KATP channels which results in a truncation of spontaneous action potentials and a decrease of hormone release.
authors: Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008, Kazan, Kremlevskii Str., 18, Russia. Electronic address: al-must@yandex.ru.
authors: Alsu N
authors: AN
authors: Mustafina
authors: Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008, Kazan, Kremlevskii Str., 18, Russia. Electronic address: alv.yakovlev@gmail.com.
authors: Aleksey V
authors: AV
authors: Yakovlev
authors: Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008, Kazan, Kremlevskii Str., 18, Russia. Electronic address: gayful_a@mail.ru.
authors: Aisylu Sh
authors: ASh
authors: Gaifullina
authors: Department of Cell Biology, University of Salzburg, Hellbrunnerstr. 34, A-5020, Salzburg, Austria. Electronic address: thomas.weiger@sbg.ac.at.
authors: Thomas M
authors: TM
authors: Weiger
authors: Department of Cell Biology, University of Salzburg, Hellbrunnerstr. 34, A-5020, Salzburg, Austria. Electronic address: anton.hermann@sbg.ac.at.
authors: Anton
authors: A
authors: Hermann
authors: Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008, Kazan, Kremlevskii Str., 18, Russia. Electronic address: sitdikovaguzel@gmail.com.
authors: Guzel F
authors: GF
authors: Sitdikova
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D045744:Cell Line, Tumor; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology; D006862:Hydrogen Sulfide / Q000378:metabolism* / Q000494:pharmacology; D054086:KATP Channels / Q000187:drug effects / Q000378:metabolism; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000172:deficiency / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D010911:Pituitary Neoplasms / Q000503:physiopathology*; D051381:Rats; D022142:Secretory Vesicles / Q000187:drug effects / Q000502:physiology; D013440:Sulfides / Q000378:metabolism / Q000494:pharmacology
chemical_list: D054086:KATP Channels; D051036:Large-Conductance Calcium-Activated Potassium Channels; D013440:Sulfides; C025451:sodium bisulfide; D006862:Hydrogen Sulfide
keywords: BK channels; Exocytosis; FM1-43; GH3 cells; Hydrogen sulfide; K(ATP) channels; Membrane potential