Ca2+-dependent nonspecific permeability of the inner membrane of liver mitochondria in the guinea fowl (Numida meleagris)

• Published in: Journal of bioenergetics and biomembranes 2015-06, Vol.47 (3), p.235-242
• Main Authors: Vedernikov, Aleksander A., Dubinin, Mikhail V., Zabiakin, Vladimir A., Samartsev, Victor N.
• Format: Article
• Language: English
• Subjects: Animal Anatomy; Animal Biochemistry; Biochemistry; Bioorganic Chemistry; Chemistry; Chemistry and Materials Science; Histology; Morphology; Organic Chemistry
• ISSN: 0145-479X; 1573-6881
• DOI: 10.1007/s10863-015-9606-z

This comparative study presents the results of the induction of Ca 2+ -dependent nonspecific permeability of the inner membrane (pore opening) of rat and guinea fowl liver mitochondria by mechanisms that are both sensitive and insensitive to cyclosporin A (CsA). It was established that energized rat and guinea fowl liver mitochondria incubated with 1 mM of inorganic phosphate (P i ) are capable of swelling upon addition of at least 125 and 875 nmol of CaCl 2 per 1 mg protein, respectively. Under these conditions, the Ca 2+ release from the mitochondria of these animals and a drop in Δψ are observed. All of these processes are inhibited by 1 μM of CsA. FCCP, causing organelle de-energization, induces pore opening in rat and guinea fowl liver mitochondria upon addition of 45 и 625 nmol of CaCl 2 per 1 mg protein, respectively. These results suggest the existence of a CsA-sensitive mechanism for the induction of Ca 2+ -dependent pores in guinea fowl liver mitochondria, which has been reported in rat liver mitochondria. However, guinea fowl liver mitochondria have a significantly greater resistance to Ca 2+ as a pore inducer compared to rat liver mitochondria. It was found that the addition of α,ω-hexadecanedioic acid (HDA) to rat and guinea fowl liver mitochondria incubated with CsA and loaded with Ca 2+ causes organelle swelling and Ca 2+ release from the matrix. It is assumed that in contrast to the CsA-sensitive pore, the CsA-insensitive pore induced by HDA in the inner membrane of guinea fowl liver mitochondria, as well as in rat liver mitochondria, is lipid in nature.