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In essence, the Goldman formula expresses the membrane potential as a weighted average of the reversal potentials for the individual ion types, weighted by permeability. (Although the membrane potential changes about 100 mV during an action potential, the concentrations of ions inside and outside the cell do not change significantly.
[1] [2] There is debate as to whether or not this channel is expressed in the cell surface membrane. [3] [4] [5] This major protein of the outer mitochondrial membrane of eukaryotes forms a voltage-dependent anion-selective channel (VDAC) that behaves as a general diffusion pore for small hydrophilic molecules.
The membrane potential is necessary for both insertion of the precursor into the carrier translocase and lateral release of the protein into the lipid phase of the inner mitochondrial membrane, which completes protein translocation. However this membrane potential-dependent process takes place in absence of ATP-driven machinery. [8]
For example, microfluorimetry is used in neurons to compare the effects of neurotoxins on both calcium ion concentration and mitochondrial membrane potential in individual cells. [5] Microfluorimetry can also be used as a method to distinguish different microorganisms from one another by analyzing and comparing the DNA content of each cell. [6]
The mitochondrial permeability transition pore (mPTP or MPTP; also referred to as PTP, mTP or MTP) is a protein that is formed in the inner membrane of the mitochondria under certain pathological conditions such as traumatic brain injury and stroke.
Mitochondria present in all cells in the human body require a resting membrane potential of the inner mitochondrial membrane to synthesize adenosine triphosphate (ATP). This membrane polarity is established through a series of proton pumps transporting hydrogen ions into the mitochondrion.
Mitochondrial outer membrane permeabilization (MOMP), also known as the mitochondrial outer membrane permeability, is one of two ways apoptosis (a type of programmed cell death) can be activated. [1] It is part of the intrinsic pathway of apoptosis, also known as the mitochondrial pathway. MOMP is known as the point of no return in apoptosis.
It can be described as the measure of the potential energy stored (chemiosmotic potential) as a combination of proton and voltage (electrical potential) gradients across a membrane. The electrical gradient is a consequence of the charge separation across the membrane (when the protons H + move without a counterion, such as chloride Cl −).