NA+/CA2+ EXCHANGE CURRENT-DENSITY IN CARDIAC MYOCYTES FROM RABBITS AND GUINEA-PIGS DURING POSTNATAL-DEVELOPMENT

被引:67
作者
ARTMAN, M
ICHIKAWA, H
AVKIRAN, M
COETZEE, WA
机构
[1] UNIV SO ALABAMA, DEPT PEDIAT, MOBILE, AL 36617 USA
[2] UNIV SO ALABAMA, DEPT MOLEC & CELLULAR PHARMACOL, MOBILE, AL 36617 USA
[3] OSAKA POLICE HOSP, OSAKA, JAPAN
[4] ST THOMAS HOSP, RAYNE INST, LONDON SE1 7EH, ENGLAND
来源
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY | 1995年 / 268卷 / 04期
关键词
NEWBORN; CARDIAC DEVELOPMENT; PATCH CLAMP;
D O I
10.1152/ajpheart.1995.268.4.H1714
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
It has been proposed that the activity of the cardiac sarcolemmal Na+/Ca2+ exchanger may be greatest in developing animals before the sarcoplasmic reticulum (SR) reaches functional maturity. Experiments were performed in rabbits, which have a sparse SR at birth, and in newborn guinea pigs, which exhibit a more extensive SR. Whole cell voltage clamp techniques were used to characterize the Ni2+-sensitive Na+/Ca2+ exchange current in single freshly isolated cardiac myocytes. Na+/Ca2+ exchange current was measured from a holding potential of -40 mV by using a slow-ramp voltage protocol (-120 to +60 mV, 0.09 Vis) in the presence of Ba2+, Cs+, tetraethylammonia, D-600, and ouabain to block Ca2+, Na+, and K+ currents. Experiments in developing rabbits (1-22 days old) demonstrated that Na+/Ca2+ exchange current density was greatest at 1-4 days and declined rapidly over the first 3 wk of age. In contrast, Na+/Ca2+ exchange current density in newborn guinea pig myocytes did not differ from that recorded in adults. These results confirm that Na+/Ca2+ exchange is functional at birth in both rabbits and guinea pigs. The species-related difference in the ontogeny of Na+/Ca2+ exchange is consistent with the concept that Na+/Ca2+ exchange assumes a relatively greater role in newborn animals with a sparse SR.
引用
收藏
页码:H1714 / H1722
页数:9
相关论文
共 30 条
[2]   SARCOLEMMAL NA+-CA-2+ EXCHANGE ACTIVITY AND EXCHANGER IMMUNOREACTIVITY IN DEVELOPING RABBIT HEARTS [J].
ARTMAN, M .
AMERICAN JOURNAL OF PHYSIOLOGY, 1992, 263 (05) :H1506-H1513
[3]   INTRACELLULAR CALCIUM HOMEOSTASIS IN CARDIAC MYOCYTES [J].
BARRY, WH ;
BRIDGE, JHB .
CIRCULATION, 1993, 87 (06) :1806-1815
[4]   STEADY-STATE MESSENGER-RNA LEVELS OF THE SARCOLEMMAL NA+-CA2+ EXCHANGER PEAK NEAR BIRTH IN DEVELOPING RABBIT AND RAT HEARTS [J].
BOERTH, SR ;
ZIMMER, DB ;
ARTMAN, M .
CIRCULATION RESEARCH, 1994, 74 (02) :354-359
[5]   DEVELOPMENTAL-CHANGES IN CARDIAC MYOCYTE CALCIUM REGULATION [J].
CHIN, TK ;
FRIEDMAN, WF ;
KLITZNER, TS .
CIRCULATION RESEARCH, 1990, 67 (03) :574-579
[6]   OXIDANT STRESS INHIBITS NA-CA-EXCHANGE CURRENT IN CARDIAC MYOCYTES - MEDIATION BY SULFHYDRYL-GROUPS [J].
COETZEE, WA ;
ICHIKAWA, H ;
HEARSE, DJ .
AMERICAN JOURNAL OF PHYSIOLOGY, 1994, 266 (03) :H909-H919
[7]   A MODEL OF CARDIAC ELECTRICAL-ACTIVITY INCORPORATING IONIC PUMPS AND CONCENTRATION CHANGES [J].
DIFRANCESCO, D ;
NOBLE, D .
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES, 1985, 307 (1133) :353-398
[8]   MEASUREMENT OF REVERSAL POTENTIAL OF NA+-CA2+ EXCHANGE CURRENT IN SINGLE GUINEA-PIG VENTRICULAR CELLS [J].
EHARA, T ;
MATSUOKA, S ;
NOMA, A .
JOURNAL OF PHYSIOLOGY-LONDON, 1989, 410 :227-249
[9]  
FABIATO A, 1979, J PHYSIOL-PARIS, V75, P463
[10]  
GOLDSTEIN M, 1985, P1