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Full Length
Research Paper
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Characterization of rat liver mitochondrial permeability
transition pore by using
mitochondrial swelling assay
Manash K. Paul1, 2*≡, Rajinder K2≡
and Anup K. Mukhopadhyay2
1Department
of Biology, Indian
Institute of Science Education and Research,
Sector-26, Chandigarh, 160019, India.
2Department
of Biotechnology, National Institute of Pharmaceutical
Education and Research, Sector-67, S.A.S. Nagar, Punjab-160
062, India.
*Corresponding author:
E-mail:
paul_cancerbiotech@yahoo.-co.in;
manash18bs@yahoo.co.in,
Phone: +919878445772.
Accepted 4 March, 2008
Accepted 4
March, 2008 |
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Abstract |
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The mitochondrial permeability transition (MPT) is
considered to contribute substantially to the regulation of
normal mitochondrial metabolism and plays as an important
mediator of cell death. MPT is regulated in a tissue
specific manner. The importance of this work is highlighted
by the fact that knowledge regarding liver MPT may serve as
important determinants of the physiological state of the
liver. Our results suggest that liver mitochondria exhibit a
cyclosporin A sensitive,
exogenous
calcium mediated
full scale MPT opening, indicative of classical MPT.
Transmission electron microscopy suggests a homogeneous
mitochondrial population. Complex II substrate
(succinate) in comparison to
complex I substrate
(NADH)
induces increased MPT opening.
Reactive Oxygen Species induces liver
mitochondrial MPT opening and is abrogated by ascorbic acid
and α-tocopherol. Liver MPT is sensitive to redox
modulation. Reducing and oxidizing agents decrease and
increase MPT opening respectively. MPT of liver mitochondria
show typical pH dependence, acidic and alkaline pH induces
MPT closure while, maximal MPT opening and calcium
sensitivity was achieved at a pH range of ~7.2-7.4. ATP
inhibited, while ADP activated MPT opening. Thus, our study
demonstrates that all the major MPT functions in normal
liver mitochondria could be determined by simple
mitochondrial swelling assay under well-defined conditions,
thereby suggesting its application in therapeutic
diagnostics.
Key
words:
Mitochondria, mitochondrial permeability transition,
swelling assay, oxidants, reductants, calcium, cyclosporin
A, pH. |
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