PMID- 22067148
OWN - NLM
STAT- MEDLINE
DCOM- 20120229
LR  - 20211021
IS  - 1542-0086 (Electronic)
IS  - 0006-3495 (Print)
IS  - 0006-3495 (Linking)
VI  - 101
IP  - 9
DP  - 2011 Nov 2
TI  - Permeabilized rat cardiomyocyte response demonstrates intracellular origin of 
      diffusion obstacles.
PG  - 2112-21
LID - 10.1016/j.bpj.2011.09.025 [doi]
AB  - Intracellular diffusion restrictions for ADP and other molecules have been 
      predicted earlier based on experiments on permeabilized fibers or cardiomyocytes. 
      However, it is possible that the effective diffusion distance is larger than the 
      cell dimensions due to clumping of cells and incomplete separation of cells in 
      fiber preparations. The aim of this work was to check whether diffusion 
      restrictions exist inside rat cardiomyocytes or are caused by large effective 
      diffusion distance. For that, we determined the response of oxidative 
      phosphorylation (OxPhos) to exogenous ADP and ATP stimulation in permeabilized 
      rat cardiomyocytes using fluorescence microscopy. The state of OxPhos was 
      monitored via NADH and flavoprotein autofluorescence. By varying the ADP or ATP 
      concentration in flow chamber, we determined that OxPhos has a low affinity in 
      cardiomyocytes. The experiments were repeated in a fluorometer on cardiomyocyte 
      suspensions leading to similar autofluorescence changes induced by ADP as 
      recorded under the microscope. ATP stimulated OxPhos more in a fluorometer than 
      under the microscope, which was attributed to accumulation of ADP in fluorometer 
      chamber. By calculating the flow profile around the cell in the microscope 
      chamber and comparing model solutions to measured data, we demonstrate that 
      intracellular structures impose significant diffusion obstacles in rat 
      cardiomyocytes.
CI  - Copyright (c) 2011 Biophysical Society. Published by Elsevier Inc. All rights 
      reserved.
FAU - Jepihhina, Natalja
AU  - Jepihhina N
AD  - Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of 
      Technology, Tallinn, Estonia.
FAU - Beraud, Nathalie
AU  - Beraud N
FAU - Sepp, Mervi
AU  - Sepp M
FAU - Birkedal, Rikke
AU  - Birkedal R
FAU - Vendelin, Marko
AU  - Vendelin M
LA  - eng
GR  - WT081755MA/Wellcome Trust/United Kingdom
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20111101
PL  - United States
TA  - Biophys J
JT  - Biophysical journal
JID - 0370626
RN  - 0 (Solutions)
RN  - 059QF0KO0R (Water)
SB  - IM
MH  - Animals
MH  - Cell Compartmentation
MH  - *Cell Membrane Permeability
MH  - Cell Respiration
MH  - Diffusion
MH  - Female
MH  - Fluorometry
MH  - Intracellular Space/*metabolism
MH  - Male
MH  - Microscopy, Fluorescence
MH  - Models, Biological
MH  - Myocytes, Cardiac/*cytology/*metabolism
MH  - Rats
MH  - Rats, Wistar
MH  - Solutions
MH  - Water
PMC - PMC3207168
EDAT- 2011/11/10 06:00
MHDA- 2012/03/01 06:00
PMCR- 2012/11/02
CRDT- 2011/11/10 06:00
PHST- 2011/06/15 00:00 [received]
PHST- 2011/08/24 00:00 [revised]
PHST- 2011/09/20 00:00 [accepted]
PHST- 2011/11/10 06:00 [entrez]
PHST- 2011/11/10 06:00 [pubmed]
PHST- 2012/03/01 06:00 [medline]
PHST- 2012/11/02 00:00 [pmc-release]
AID - S0006-3495(11)01085-X [pii]
AID - BPJ3165 [pii]
AID - 10.1016/j.bpj.2011.09.025 [doi]
PST - ppublish
SO  - Biophys J. 2011 Nov 2;101(9):2112-21. doi: 10.1016/j.bpj.2011.09.025. Epub 2011 
      Nov 1.