CALCIUM-ACTIVATED K+ CHANNELS AS MODULATORS OF HUMAN MYOMETRIAL CONTRACTILE ACTIVITY

被引:138
作者
ANWER, K
OBERTI, C
PEREZ, GJ
PEREZREYES, N
MCDOUGALL, JK
MONGA, M
SANBORN, BM
STEFANI, E
TORO, L
机构
[1] UNIV TEXAS, SCH MED, DEPT BIOCHEM & MOLEC BIOL, HOUSTON, TX 77030 USA
[2] UNIV TEXAS, SCH MED, DEPT OBSTET, HOUSTON, TX 77030 USA
[3] UNIV TEXAS, SCH MED, DEPT GYNECOL & REPROD SCI, HOUSTON, TX 77030 USA
[4] FRED HUTCHINSON CANC RES CTR, SEATTLE, WA 98104 USA
[5] UNIV WASHINGTON, DEPT PATHOL, SEATTLE, WA 98195 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY | 1993年 / 265卷 / 04期
关键词
HUMAN MYOMETRIUM; SMOOTH MUSCLE; UTERUS; IBERIOTOXIN; INTRACELLULAR FREE CALCIUM; MEMBRANE POTENTIAL; INOSITOL PHOSPHATES;
D O I
10.1152/ajpcell.1993.265.4.C976
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
The role of Ca2+-activated potassium (K(Ca)) channels in the regulation of membrane potential, intracellular free calcium ([Ca2+]i) and contraction was investigated in uterine smooth muscle and myometrial cells. In an immortalized human myometrial cell line, oxytocin increased [Ca2+]i and [H-3]inositol phosphate formation. Relaxin attenuated the oxytocin-induced increase in [Ca2+]i. In cell-attached patches, membrane depolarization activated a large-conductance K(Ca) channel (179 +/- 4 pS). Iberiotoxin (IbTX), a potent blocker of ''maxi'' K(Ca) channels (A. Galvez, G. Gimenez-Gallego, J. P. Reuben, L. Roy-Contanciin, P. Feigenbaum, G. J. Kaczorowski, and M. L. Garcia. J. Biol. Chem. 265: 11083-11090, 1990) produced long closed events (approximately 6 min) in these channels. In agreement with this blockage, IbTX depolarized the cells by 9.8 +/- 2.8 mV and caused a dose-dependent increase in [Ca2+], with a half-maximal effective concentration of 0.79 nM. IbTX also caused phasic contractions in human myometrial strips and increased both the frequency and force of spontaneous contractions in estrogen-primed rat myometrial strips. Moreover, myometrial contractility was also affected by 1 mM tetraethylammonium, a concentration that blocks uterine smooth muscle K(Ca) channels when applied to the extracellular side (G. J. Perez, L. Toro, S. D. Erulkar, and E. Stefani. Am. J. Obstet. Gynecol. 168: 652-660, 1993). These results strongly suggest that the large conductance K(Ca) channels may actively participate in the control of human myometrial cell membrane potential and [Ca2+]i.
引用
收藏
页码:C976 / C985
页数:10
相关论文
共 45 条
[1]  
ADELMAN JP, 1992, NEURON, V9, P1
[2]   CA-2+ ACTIVATED K+ CHANNELS IN PREGNANT RAT MYOMETRIUM - MODULATION BY A BETA-ADRENERGIC AGENT [J].
ANWER, K ;
TORO, L ;
OBERTI, C ;
STEFANI, E ;
SANBORN, BM .
AMERICAN JOURNAL OF PHYSIOLOGY, 1992, 263 (05) :C1049-C1056
[3]   ANTAGONISM OF CONTRACTANTS AND RELAXANTS AT THE LEVEL OF INTRACELLULAR CALCIUM AND PHOSPHOINOSITIDE TURNOVER IN THE RAT UTERUS [J].
ANWER, K ;
HOVINGTON, JA ;
SANBORN, BM .
ENDOCRINOLOGY, 1989, 124 (06) :2995-3002
[4]   PREGNANCY SUPPRESSES G-PROTEIN COUPLING TO PHOSPHOINOSITIDE HYDROLYSIS IN GUINEA-PIG MYOMETRIUM [J].
ARKINSTALL, SJ ;
JONES, CT .
AMERICAN JOURNAL OF PHYSIOLOGY, 1990, 259 (01) :E57-E65
[5]   INFLUENCE OF CHRONIC ESTROGEN-TREATMENT ON THE DENSITY OF MUSCARINIC CHOLINERGIC RECEPTORS AND CALCIUM CHANNELS IN THE RABBIT UTERUS [J].
BATRA, S .
JOURNAL OF ENDOCRINOLOGY, 1990, 125 (02) :185-189
[6]   HORMONAL-REGULATION OF K+-CHANNEL MESSENGER-RNA IN RAT MYOMETRIUM DURING ESTRUS CYCLE AND IN PREGNANCY [J].
BOYLE, MB ;
MACLUSKY, NJ ;
NAFTOLIN, F ;
KACZMAREK, LK .
NATURE, 1987, 330 (6146) :373-375
[7]   REGULATION OF ARTERIAL TONE BY ACTIVATION OF CALCIUM-DEPENDENT POTASSIUM CHANNELS [J].
BRAYDEN, JE ;
NELSON, MT .
SCIENCE, 1992, 256 (5056) :532-535
[8]  
CANDIA S, 1992, BIOPHYS J, V63, P1
[9]   MEMBRANE POTENTIAL AND IONIC CONTENT IN PREGNANT AND NON-PREGNANT RAT MYOMETRIUM [J].
CASTEELS, R ;
KURIYAMA, H .
JOURNAL OF PHYSIOLOGY-LONDON, 1965, 177 (02) :263-&
[10]  
FABIATO A, 1988, METHOD ENZYMOL, V157, P378