Skeletal muscle relaxants depolarizing

L C. Rapacuronium is a skeletal muscle relaxant that works by competing with ACh for receptors at the postjunctional membrane. Nicotine and succinylcholine also act at the end plate receptors but cause depolarization. Hexamethonium is a ganglion blocker that has essentially no activity at the end plate receptors, and scopolamine blocks cholinergic muscarinic receptors and thus does not act at the end plate receptors. 

Muscle contraction responses to different patterns of nerve stimulation used in monitoring skeletal muscle relaxation. The alterations produced by a nondepolarizing blocker and depolarizing and desensitizing blockade by succinylcholine are shown. In the train of four (TOF) pattern, four stimuli are applied at 2 Hz. The TOF ratio (TOF-R) is calculated from the strength of the fourth contraction divided by that of the first. In the double burst pattern, three stimuli are applied at 50 Hz, followed by a 700 ms rest period and then repeated. In the posttetanic potentiation pattern, several seconds of 50 Hz stimulation are applied, followed by several seconds of rest and then by single stimuli at a slow rate (eg, 0.5 Hz). The number of detectable posttetanic twitches is the posttetanic count (PTC)., first posttetanic contraction. 

Succinylcholine is an ultra-short-acting depolarizing skeletal muscle relaxant. The neuromuscular block remains for as long as sufficient quantities of succinylcholine remain. After i.v. administration, the onset of action is typically within Imin and lasts for 2-3 min. Succinylcholine is metabolized by plasma cholinesterases to choline and the weakly active succinylmono-choline, which is primarily excreted in the urine (Plumb 1995). Succinylcholine should be administered i.v. at a dose rate of 0.088mg/kg (Plumb 1995). Succinylcholine can also be added to an overdose of barbiturate to produce euthanasia in horses. This is accompanied by a minimal amount of postmortem muscular contraction, making the addition of succinylcholine desirable for use during euthanasia when the client is present. 

SUtilains [ban, inn, usan] (BAX 1515 Travase ) is an ENZYME derived from Bacillus subtilis. It is a proteolytic enzyme used for wound debridement in moist conditions, suxamethonium chloride [ban. inn] (succinyichoiine chloride [usan] suxamethonium bromide [ban] succinoylcholine Scoline Quelicin Anectine ) is a bistrimethylethanaminium derivative, a NICOTINIC CHOLINOCEPTOR AGONIST, a (depolarizing) NEUROMUSCULAR BLOCKING AGENT, which can be used as a SKELETAL MUSCLE RELAXANT in anaesthesia relaxant. Its action is short-lived due to hydrolysis by plasma cholinesterase, suxamethonium bromide suxamethonium chloride. 

Indications Skeletal muscle relaxation during general anesthesia Category Cholinesterase inhibitor Depolarizing muscle relaxant Half-life N/A... 

Succinylcholine, a depolarizing neuromuscular blocking agent (0.3 to 1.1 mg/kg IV over 10 to 30 seconds), is used to induce skeletal muscle relaxation to facilitate intubation, ventilation, or orthopedic manipulations and to lessen muscular contraction in convulsions induced by physicians. A peripheral nerve stimulator may be used to monitor effects and degree of blockade. 

Succinylcholine is an ultra-short-acting depolarizing skeletal muscle relaxant. Paralysis usually appears in the following muscles consecutively levator muscles of the eyelids, muscles of mastication, limb muscles, abdominal muscles, muscles of the glottis, and finally, the intercostals, the diaphragm, and all other skeletal muscles. Recovery of normal muscle tone follows the reverse order. 

Explain the action of depolarizing blockers in skeletal muscle relaxation. 

De urane produces direct skeletal muscle relaxation and enhances the effects of nondepolarizing and depolarizing neuromuscular blocking agents. Consistent with its minimal metabolism, desflurane has no reported nephrotoxicity or hepatotoxicity. 

Muscle Sevoflurane produces skeletal muscle relaxation and enhances the effects of nondepolarizing and depolarizing neuromuscular blocking agents. 

The skeletal muscle relaxants provide muscle relaxation and/or immobility via N-receptor interactions. Most, including otubocurarine, atracurium, and mivacurium, are competitive and nondepolarizing and can be reversed by AQiE inhibitors. Sucdnylcholine is a depolarizing, noncompetitive agonist... 

In muscle cells, the contraction is induced by Ca2+ release from the sarcoplasmic reticulum, as a result of membrane depolarization and activation of RyRl receptors located at the surface of the SR. The subsequent transport of cytoplasmic Ca2+ back into the lumen of the sarcoplasmic reticulum restores low resting calcium levels and allows muscle relaxation. In fast-twitch skeletal muscle fibers, Ca2+ uptake is mediated by the sarco(endo)plasmic reticulum Ca2+ ATPase SERCA1 which represents more than 99% of SERCA isoforms in these muscle fibers. 

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