Depolarizing blockers act on skeletal muscle fibers' membranes and induce their depolarization. Most depolarizing blockers have two quaternary N+ atoms that bind the nicotinic acetylcholine receptors and cause neuromuscular blockade within minutes.
Succinylcholine is the most commonly used depolarizing blocker. Chemically, it constitutes two molecules of acetylcholine joined together by an acetate methyl group. They act on the receptors in the same way as acetylcholine. Because...

The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...

Restless Leg Syndrome (RLS), also known as Willis-Ekbom disease, is a neurological disorder characterized by an uncontrollable urge to move the legs due to uncomfortable sensations. These sensations typically occur during periods of rest or inactivity, particularly when lying down or sitting, and can severely disrupt sleep.
The exact cause of RLS is not fully understood, but it is believed to involve dopamine, a neurotransmitter that helps regulate muscle movement. Imbalances in dopamine levels...

Panic disorder is an anxiety disorder characterized by recurrent and sudden minutes-long episodes of intense fear, known as panic attacks. These attacks may feel like heart attacks and often happen without warning or a specific cause. They can include symptoms such as rapid heart rate, shortness of breath, chest pain, trembling, sweating, dizziness, and a sense of helplessness. During a panic attack, individuals may feel as though they are experiencing a heart attack or are in a...

Narcolepsy is a chronic sleep disorder characterized by pervasive, uncontrolled sleepiness and other sleep disturbances. One of its hallmark symptoms is an abrupt transition to REM sleep upon falling asleep, which causes symptoms typically associated with this phase to occur unexpectedly during wakefulness. These include the following symptoms, which typically last from a minute or two to half an hour.

Depolarizing blockers are administered through intravenous injection. Succinylcholine is the most common choice of depolarizing blockers in emergency clinical practices. Although they have a rapid onset, they readily diffuse away from the motor end plate into the extracellular fluid. They are metabolized by enzymes such as liver butyrylcholinesterase and plasma pseudocholinesterases. This produces a short duration of action, typically 5-10 minutes long, unlike nondepolarizing blockers, which...