Related Experiment Video
Updated: Apr 18, 2026

Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling
Published on: August 1, 2016
[H+-Ca2+-exchanger in the myometrium mitochondria: modulation of exogenous and endogenous compounds]
Abstract:
The properties of ΔpH-induced Ca2+-transport from isolated rat myometrium mitochondria was investigated. Ca2+-accu- mulation was carried out in the presence of Mg-ATP2- and succinate. Transport of Ca2+ recorded using Ca2+-sensitive fluorescent probe Fluo-4 AM. It is shown that acidification of extramitochondrial medium is accompanied by stimulation of Ca2+ release from mitochondria. This process is insensitive to the tetraphenylphosphonium which is relatively specific Na+-Ca2+-exchanger inhibitor of mitochondrial inner membrane, but inhibited in the presence of monoclonal antibodies directed against the protein LETM1 (Anti-LETM1). LETM1 protein in some tissues is the molecular basis of the H+-Ca2+-exchanger functioning on mitochondria. It was found that the H+-Ca2+-exchanger is stimulated by 100 μM amiloride (diuretic) and inhibited by Mg ions in milimolar concentrations. The transport system was completely resistant to the action of nitric oxide (sodium nitroprusside and sodium nitrite), but was stimulated by macrocyclic compounds of Calixarenes (C-97 and C-99) in submicromolar concentrations. Thus, the mitochondria of rat myometrium probably not have a system of Na+-Ca2+-exchanger, and provide the maintenance of the matrix Ca2+-homeostasis with H+-Ca2+-exchanger. Since the transport system high affinity activated by Calixarenes, further investigation of the influence of these compounds on the transport process makes promising.
More Related Videos
11:00Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes
Published on: September 18, 2017
10:30Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles
Published on: October 15, 2014
Related Concept Videos
Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
Actin and Myosin in Muscle Contraction
Excitation-Contraction Coupling in Skeletal Muscles
When an action...
Cross-bridge Cycle
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open....
Microscopic Anatomy of Skeletal Muscles
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...