What is resting mitochondrial membrane potential?

What is resting mitochondrial membrane potential?

Mitochondrial membrane potential (ΔΨM) is a central intermediate in oxidative energy metabolism. In cultured rat cortical neurons, ΔΨM is −139 mV at rest, and is regulated between −108 mV and −158 mV by concerted increases in ATP demand and Ca2+-dependent metabolic activation.

What is mitochondrial membrane potential assay?

The Mitochondrial Membrane Potential Assay Kit (II) is a fluorescent assay that detects the mitochondrial membrane potential in living cells. TMRE is a cell membrane permeable, fluorescent dye that accumulates in intact mitochondria.

What is TMRM bind?

As discussed in Results, TMRM, TMRE, and R123 were found to bind to mitochondria, causing an apparent deviation of the ΔΨ-dependent accumulation of these probes from that predicted by the Nernst equation.

How do you measure mitochondrial potential?

Mitochondrial function, a key indicator of cell health, can be assessed by monitoring changes in mitochondrial membrane potential (MMP). Cationic fluorescent dyes are commonly used tools to assess MMP. We used a water-soluble mitochondrial membrane potential indicator (m-MPI) to detect changes in MMP in HepG2 cells.

What is the meaning of resting potential?

Resting potential, the imbalance of electrical charge that exists between the interior of electrically excitable neurons (nerve cells) and their surroundings. If the inside of the cell becomes less negative (i.e., the potential decreases below the resting potential), the process is called depolarization.

What does a positive membrane potential mean?

Membrane potential is a potential gradient that forces ions to passively move in one direction: positive ions are attracted by the ‘negative’ side of the membrane and negative ions by the ‘positive’ one.

What does membrane potential measure?

The membrane potential is the difference in electrical charge between the inside and the outside of the neuron. This is measured using two electrodes. A reference electrode is placed in the extracellular solution. The recording electrode is inserted into the cell body of the neuron.

What is mitochondrial hyperpolarization?

Mitochondrial hyperpolarization (MHP), an early event of T-cell activation and death, appears to be mediated through inhibition of F0F1-ATPase or dephosphorylation of cytochrome c oxidase [44].

Is TMRM toxic?

However, up to 2 µM TMRM is apparently not toxic. You may not see the toxic effects without simultaneous respirometry, but that does not mean they are not there then.

What is the mitochondrial membrane?

As previously mentioned, mitochondria contain two major membranes. The outer mitochondrial membrane fully surrounds the inner membrane, with a small intermembrane space in between. The outer membrane has many protein-based pores that are big enough to allow the passage of ions and molecules as large as a small protein.

What causes resting potential?

The resting potential is determined by concentration gradients of ions across the membrane and by membrane permeability to each type of ion. Ions move down their gradients via channels, leading to a separation of charge that creates the resting potential.

What happens when tmrm is lost in the mitochondria?

Tetramethylrhodamine, methyl ester (TMRM) is a cell-permeant dye that accumulates in active mitochondria with intact membrane potentials. If the cells are healthy and have functioning mitochondria, the signal is bright. Upon loss of the mitochondrial membrane potential, TMRM accumulation ceases and the signal dims or disappears.

How are tmrm and R123 used to measure mitochondrial membrane potential?

TMRM, TMRE, and R123 were dissolved in methanol and used directly. The methanol concentrations in all incubations of mitochondria were kept to <0.5% (v/v). TMRM and TMRE were obtained from Molecular Probes (Eugene, OR). R123 and all other chemicals were from Sigma Chemical Co. (St. Louis, MO).

How is the mitochondrial transmembrane potential related to the oxidative process?

Mitochondria provide the majority of this ATP by a process known as oxidative phosphorylation. This process involves active transfer of positively charged protons across the mitochondrial inner membrane resulting in a net internal negative charge, known as the mitochondrial transmembrane potential (ΔΨm).

Where does tetramethylrhodamine accumulate in the mitochondria?

Tetramethylrhodamine, methyl ester (TMRM) is a cell-permeant dye that accumulates in active mitochondria with intact membrane potentials. If the cells are healthy and have functioning mitochondria, the signal is bright.