PMID- 9116325
OWN - NLM
STAT- MEDLINE
DCOM- 19970424
LR  - 20191210
IS  - 0867-5910 (Print)
IS  - 0867-5910 (Linking)
VI  - 47
IP  - 4
DP  - 1996 Dec
TI  - Effect of sarcoplasmic reticulum Ca release into diadic region on Na/Ca exchange 
      in cardiac myocytes.
PG  - 577-90
AB  - The hypothesis that sarcoplasmic reticulum (SR) generates subsarcolemmal [Ca] 
      higher than that in the bulk of sarcoplasm and that it affects the rate of Na+Ca 
      exchange were tested. Voltage clamped cardiomyocytes of guinea-pigs and rats were 
      stimulated by pre-pulses from a holding potential of -80 mV to -40 mV (20 ms) 
      followed by 200 ms depolarizations to +5 mV. Single 5, 10, 20, 30, 50, 100 and 
      300 ms depolarizations were interposed between 200 ms pulses. The amplitude of 
      the tail (Na/Ca exchange) currents recorded upon repolarization were compared 
      with instantaneous fluorescence on Indo 1 loaded into cells. In both species 
      amplitude of the tail currents were higher during the ascending phase of the Ca 
      transient than during the descending phase, although the fluorescence was lower. 
      The dissociation was abolished by thapsigargin (TG), the blocker of the SR 
      Ca-ATPase. The results suggest that over the initial < 50 ms of the transient the 
      Na/Ca exchangers are exposed to [Ca] higher than that in the bulk sarcoplasm and 
      that it is generated by the SR.
FAU - Lewartowski, B
AU  - Lewartowski B
AD  - Department of Clinical Physiology, Medical Center of Postgraduate Education, 
      Warsaw, Poland.
FAU - Janiak, R
AU  - Janiak R
FAU - Langer, G A
AU  - Langer GA
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Poland
TA  - J Physiol Pharmacol
JT  - Journal of physiology and pharmacology : an official journal of the Polish 
      Physiological Society
JID - 9114501
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Indoles)
RN  - 67526-95-8 (Thapsigargin)
RN  - 9NEZ333N27 (Sodium)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - N18RMK75W1 (indo-1)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Calcium/*metabolism
MH  - Calcium-Transporting ATPases/antagonists & inhibitors
MH  - Enzyme Inhibitors/pharmacology
MH  - Guinea Pigs
MH  - Indoles
MH  - Membrane Potentials/drug effects
MH  - Myocardium/cytology/*metabolism
MH  - Patch-Clamp Techniques
MH  - Rats
MH  - Sarcoplasmic Reticulum/*metabolism
MH  - Sodium/*metabolism
MH  - Thapsigargin/pharmacology
EDAT- 1996/12/01 00:00
MHDA- 1996/12/01 00:01
CRDT- 1996/12/01 00:00
PHST- 1996/12/01 00:00 [pubmed]
PHST- 1996/12/01 00:01 [medline]
PHST- 1996/12/01 00:00 [entrez]
PST - ppublish
SO  - J Physiol Pharmacol. 1996 Dec;47(4):577-90.