Chunk #21 — Epigenetics-Relevant Consequences of Oxidative Alcohol Metabolism — Increases in NADH/NAD+ Ratio and Their Consequences — Modulation of the MPT Opening
MPT is defined as an increase in the ability of the membranes surrounding the mitochondria to allow passage of molecules of a certain size (i.e., increase in membrane permeability). This increase in permeability, which results from the opening of specific pores, typically occurs in response to certain pathological conditions and can lead to mitochondrial swelling and cell death through apoptosis or necrosis. Increases in NADH/NAD+ ratio resulting from ethanol metabolism lead to an increase in MPT opening, which significantly influences mitochondrial membrane potential (Zoratti and Szabo 1995). In addition, NADH can have other effects, such as increased release of calcium ions (Ca++) release from certain channels on the ER, as demonstrated in a cell line called PC12 cells (Kaplin et al. 1996), and inhibition of ryanodine receptors of cardiac muscles (Zima et al. 2003).
