ISSN 2326-7267
International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 1 (1), pp. 001-008, December, 2010. © International Scholars Journals
Full Length Research Paper
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.
Accepted 14 September, 2010
Abstract
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 -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.