Spontaneous electrical activity and associated changes in calcium concentration in guinea-pig gastric smooth muscle

被引:46
作者
Fukuta, H [1 ]
Kito, Y [1 ]
Suzuki, H [1 ]
机构
[1] Nagoya City Univ, Sch Med, Dept Physiol, Mizuho Ku, Nagoya, Aichi 4678601, Japan
来源
JOURNAL OF PHYSIOLOGY-LONDON | 2002年 / 540卷 / 01期
关键词
D O I
10.1113/jphysiol.2001.013306
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Spontaneous electrical activity and internal Ca2+ concentration ([Ca2+](i)) were measured simultaneously using conventional microelectrodes and fura-2 fluorescence, respectively, in isolated circular smooth muscle bundles of the guinea-pig gastric antrum. The smooth muscle bundles generated periodic slow potentials with accompanying spike potentials and associated transient increases in [Ca2+](i) (Ca2+-transients). Nifedipine abolished the spike potentials but not the slow potentials, and reduced the amplitude of associated Ca2+-transients. Caffeine, in the absence or presence of ryanodine, reduced resting [Ca2+], levels and abolished the slow potentials and associated Ca2+-transients. Depolarization elevated and hyperpolarization reduced resting [Ca2+](i) levels with associated changes in the frequency of slow potentials. The amplitude of Ca2+-transients changed in a bell-shaped manner with the membrane potential change. Slow potentials and associated Ca2+-transients were abolished if [Ca2+](i) levels were reduced by BAPTA-AM or if the internal Ca2+ pump was inhibited by cyclopiazonic acid. 2-Aminoethoxy-diphenylborate (2-APB), a known inhibitor of inositol trisphosphate UN-mediated Ca2+ release, also blocked slow potentials and Ca2+-transients. Carbonyl cyanide m-chlorophenyl hydrazone (CCCP), a mitochondrial protonophore, depolarized the membrane, elevated [Ca2+](i) levels and abolished slow potentials and Ca2+-transients. Inhibition of mitochondrial ATP-sensitive K+ channels by glybenclamide and 5-hydroxydecanoic acid (5-HAD) abolished slow potentials and Ca2+ transients, without altering the smooth muscle [Ca2+](i). It is concluded that in antrum circular muscles, the frequency of slow potentials is correlated with the level of [Ca2+](i). The slow potential is coupled to release of Ca2+ from an internal store, possibly through the activation Of IP3 receptors; this may be initiated by the activation of ATP-sensitive K+ channels in mitochondria following Ca2+ handling by mitochondria.
引用
收藏
页码:249 / 260
页数:12
相关论文
共 45 条
  • [1] Arnaud M J, 1987, Prog Drug Res, V31, P273
  • [2] INOSITOL TRISPHOSPHATE AND CALCIUM SIGNALING
    BERRIDGE, MJ
    [J]. NATURE, 1993, 361 (6410) : 315 - 325
  • [3] Interstitial cells of Cajal in the guinea-pig gastrointestinal tract as revealed by c-Kit immunohistochemistry
    Burns, AJ
    Herbert, TM
    Ward, SM
    Sanders, KM
    [J]. CELL AND TISSUE RESEARCH, 1997, 290 (01) : 11 - 20
  • [4] Photodynamic triggering of calcium oscillation in the isolated rat pancreatic acini
    Cui, ZJ
    Kanno, T
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1997, 504 (01): : 47 - 55
  • [5] Identification of rhythmically active cells in guinea-pig stomach
    Dickens, EJ
    Hirst, GDS
    Tomita, T
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1999, 514 (02): : 515 - 531
  • [6] Selective knockout of intramuscular interstitial cells reveals their role in the generation of slow waves in mouse stomach
    Dickens, EJ
    Edwards, FR
    Hirst, GDS
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 2001, 531 (03): : 827 - 833
  • [7] Contributions of mitochondria to animal physiology: from homeostatic sensor to calcium signalling and cell death
    Duchen, MR
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1999, 516 (01): : 1 - 17
  • [8] Unitary nature of regenerative potentials recorded from circular smooth muscle of guinea-pig antrum
    Edwards, FR
    Hirst, GDS
    Suzuki, H
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1999, 519 (01): : 235 - 250
  • [9] FUKUTA H, 1999, JPN J PHYSIOL S1, V49, pS101
  • [10] MEMBRANE-POTENTIAL MODULATES INOSITOL 1,4,5-TRISPHOSPHATE-MEDIATED CA2+ TRANSIENTS IN GUINEA-PIG CORONARY MYOCYTES
    GANITKEVICH, VY
    ISENBERG, G
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1993, 470 : 35 - 44