regulation of excitatory postsynaptic membrane potential involved in skeletal muscle contraction

Definition

Target type: biologicalprocess

Any process, involved in skeletal muscle contraction, that modulates the establishment or extent of the excitatory postsynaptic potential (EPSP). Excitatory postsynaptic potential (EPSP) is a temporay increase in postsynaptic potential due to the flow of positively charged ions into the postsynaptic cell. The flow of ions that causes an EPSP is an excitatory postsynaptic current (EPSC) and makes it easier for the neuron to fire an action potential. [GOC:ef, GOC:mtg_muscle]

Regulation of excitatory postsynaptic membrane potential involved in skeletal muscle contraction is a complex process that involves the coordinated action of multiple proteins and signaling pathways. The process begins with the release of acetylcholine (ACh) from the motor neuron at the neuromuscular junction. ACh binds to nicotinic acetylcholine receptors (nAChRs) on the muscle fiber membrane, leading to depolarization of the muscle cell membrane. This depolarization triggers an action potential that travels along the muscle fiber membrane and into the T-tubules. The T-tubules are invaginations of the sarcolemma that extend deep into the muscle fiber, allowing the action potential to reach the sarcoplasmic reticulum (SR). The SR is a network of interconnected membrane-bound sacs that store calcium ions (Ca2+). The arrival of the action potential at the SR triggers the release of Ca2+ from the SR into the sarcoplasm, the cytoplasm of the muscle fiber. The increase in Ca2+ concentration in the sarcoplasm initiates the process of muscle contraction. Ca2+ binds to the troponin complex, which is a protein that is bound to the thin filament of the sarcomere. Troponin is made up of three subunits: troponin C (TnC), troponin I (TnI), and troponin T (TnT). TnC binds to Ca2+, TnI binds to the actin filament, and TnT binds to tropomyosin, another protein that is bound to the actin filament. When Ca2+ binds to TnC, the troponin complex undergoes a conformational change that causes tropomyosin to move away from the binding sites for myosin on the actin filament. This allows the myosin heads to bind to the actin filament and initiate the power stroke, which is the process that drives muscle contraction. The power stroke is driven by the hydrolysis of ATP. After the power stroke, the myosin head detaches from the actin filament and re-binds to another actin binding site further along the filament. This process repeats, causing the thin filament to slide along the thick filament and shorten the sarcomere. Muscle relaxation occurs when Ca2+ is removed from the sarcoplasm. This is achieved by the active transport of Ca2+ back into the SR by the Ca2+ ATPase pump. As Ca2+ levels decrease in the sarcoplasm, the troponin complex returns to its resting conformation, blocking the myosin binding sites on the actin filament. This prevents further contraction and allows the muscle to relax.'
"

Proteins (1)

Compounds (77)