Mitochondrial bioenergetics as affected by cationic detergents

This paper examines the accumulation and toxicity mechanism of a cationic detergent, cetyltrimethylammonium (bromide) (CTAB), in energized rat liver mitochondria. The results suggest that: (1) the CTAB ion is accumulated in the mitochondrial matrix by a membrane potential-driven uptake mechanism; (2) accumulation may lead to a toxic effect, since it gives rise to collapse of the mitochondrial membrane potential (delta phi) which is correlated with ATP synthesis and which regulates Ca++ uptake; (3) collapse of delta phi may be due to enhanced permeability of the mitochondrial membrane to the ions (detergent effect); and (4) delta phi collapse and Ca++ and K+ release were also observed in another cationic detergent, NTAB, but not in the presence of anionic detergents.