title: Effects of exposure to a time-varying 1.5 T magnetic field on the neurotransmitter-activated increase in intracellular Ca(2+) in relation to actin fiber and mitochondrial functions in bovine adrenal chromaffin cells.
abstract: BACKGROUND
  It has been reported that exposure to electromagnetic fields influences intracellular signal transduction. We studied the effects of exposure to a time-varying 1.5 T magnetic field on membrane properties, membrane cation transport and intracellular Ca(2+) mobilization in relation to signals. We also studied the mechanism of the effect of exposure to the magnetic field on intracellular Ca(2+) release from Ca(2+) stores in adrenal chromaffin cells.
  
  
  METHODS
  We measured the physiological functions of ER, actin protein, and mitochondria with respect to a neurotransmitter-induced increase in Ca(2+) in chromaffin cells exposed to the time-varying 1.5 T magnetic field for 2h.
  
  
  RESULTS
  Exposure to the magnetic field significantly reduced the increase in [Ca(2+)]i. The exposure depolarized the mitochondria membrane and lowered oxygen uptake, but did not reduce the intracellular ATP content. Magnetic field-exposure caused a morphological change in intracellular F-actin. F-actin in exposed cells seemed to be less dense than in control cells, but the decrease was smaller than that in cytochalasin D-treated cells. The increase in G-actin (i.e., the decrease in F-actin) due to exposure was recovered by jasplakinolide, but inhibition of Ca(2+) release by the exposure was unaffected.
  
  
  CONCLUSIONS
  These results suggest that the magnetic field-exposure influenced both the ER and mitochondria, but the inhibition of Ca(2+) release from ER was not due to mitochondria inhibition. The effect of eddy currents induced in the culture medium may indirectly influence intracellular actin and suppress the transient increase in [Ca(2+)]i.
authors.affiliation: Department of Human Welfare, Faculty of Health and Welfare, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan. ikehara@tks.bunri-u.ac.jp
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Ikehara
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Nishisako
authors.forename: Yuki
authors.initials: Y
authors.lastname: Minami
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ichinose Sasaki
authors.forename: Tairo
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kitamura
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shono
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Houchi
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kawazoe
authors.forename: Kazuo
authors.initials: K
authors.lastname: Minakuchi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yoshizaki
authors.forename: Yohsuke
authors.initials: Y
authors.lastname: Kinouchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyamoto
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D008841:Actin Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000311:Adrenal Glands / Q000166:cytology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D003078:Colchicine / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D047630:Depsipeptides / Q000494:pharmacology; D004574:Electromagnetic Fields; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D015151:Immunoblotting; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D018377:Neurotransmitter Agents / Q000494:pharmacology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D013997:Time Factors; D050257:Tubulin Modulators / Q000494:pharmacology
chemical_list: D000199:Actins; D047630:Depsipeptides; D018377:Neurotransmitter Agents; D019384:Nucleic Acid Synthesis Inhibitors; D050257:Tubulin Modulators; C057531:jasplakinolide; D015638:Cytochalasin D; D000255:Adenosine Triphosphate; D000109:Acetylcholine; D003078:Colchicine; D002118:Calcium