The generation of free acid SBFI within the matrix of isolated rat heart mitochondria and its use to estimate matrix [Na+

Abstract

processes (e.g. [ 1 4 ) . (However, it should be appreciated that, thus far, this has only been d y satisfactorily achieved with heart mitochondria, chiefly 6rom rat, although some attempts have been made with mitochondria fran liver 13.53). Similarly, fluoresctnt H+ indicators such as BCECF have been used to estimate matrix pH [ 1.31. and more recently the Mg2+-sensitive mag-fura-2 and magi n h l have been used to obtain estimates of matrix Mg2+ [6,7]. It is important to obrain mcasu~cmcnts of these ion concentrations, as they ~ T C all now appnxiated as being impatant in thecontrol of oxidative metabolism, and other events, within the matrix 181. Matrix Ca2+ in particular, and hence also its transport mchanisms. am now widely r ~ ~ ~ g n i s c d as having a key signal transduction role as pan of the mssengcr function of Ca2+ in numnuhn * tissues [8]. It achieves this through its activation of three key inmmimchondrid enzymes, the p vate (PDH), NAD+-isocitrate (ICDH) and 2-