Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026838 (spasticity)
 6,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malignant hyperthermia (MH) is a genetic, potentially life-threatening disorder of the skeletal muscle presenting during or following general anaesthesia. Trigger agents are volatile anaesthetics and depolarising muscle relaxants. Dantrolene is the only available drug for effective and specific MH therapy, which reduces significantly the mortality rate. Dantrolene is a skeletal muscle relaxant that depresses the excitation-contraction coupling,however, the specificity of action remains unknown. Recent studies identified the ryanodine receptor, the calcium release channel of the sarcoplasmic reticulum, as the direct molecular target of dantrolene. In addition to its use for MH, dantrolene is used in other disorders such as neuroleptic malignant syndrome and spasticity. Since dantrolene is weakly water soluble, the clinical preparation is time and manpower consuming. New agents have been synthesized, but because of economic considerations no registration for clinical usage has been realised.
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PMID:[Dantrolene. Pharmacological and therapeutic aspects]. 1266 6

Human malignant hyperthermia is a life-threatening genetic sensitivity of skeletal muscles to volatile anaesthetics and depolarizing neuromuscular blocking drugs occurring during or after anaesthesia. The skeletal muscle relaxant dantrolene is the only currently available drug for specific and effective therapy of this syndrome in man. After its introduction, the mortality of malignant hyperthermia decreased from 80% in the 1960s to < 10% today. It was soon discovered that dantrolene depresses the intrinsic mechanisms of excitation-contraction coupling in skeletal muscle. However, its precise mechanism of action and its molecular targets are still incompletely known. Recent studies have identified the ryanodine receptor as a dantrolene-binding site. A direct or indirect inhibition of the ryanodine receptor, the major calcium release channel of the skeletal muscle sarcoplasmic reticulum, is thought to be fundamental in the molecular action of dantrolene in decreasing intracellular calcium concentration. Dantrolene is not only used for the treatment of malignant hyperthermia, but also in the management of neuroleptic malignant syndrome, spasticity and Ecstasy intoxication. The main disadvantage of dantrolene is its poor water solubility, and hence difficulties are experienced in rapidly preparing intravenous solutions in emergency situations. Due to economic considerations, no other similar drugs have been introduced into routine clinical practice.
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PMID:Dantrolene--a review of its pharmacology, therapeutic use and new developments. 1547 27

Dantrolene is the drug of choice for the treatment of malignant hyperthermia (MH) and is also useful for treatment of spasticity or muscle spasms associated with several clinical conditions. The current study examines the mechanisms of dantrolene's action on skeletal muscle and shows that one of dantrolene's mechanisms of action is to block excitation-coupled calcium entry (ECCE) in both adult mouse flexor digitorum brevis fibers and primary myotubes. A second important new finding is that myotubes isolated from mice heterozygous and homozygous for the ryanodine receptor type 1 R163C MH susceptibility mutation show significantly enhanced ECCE rates that could be restored to those measured in wild-type cells after exposure to clinical concentrations of dantrolene. We propose that this gain of ECCE function is an important etiological component of MH susceptibility and possibly contributes to the fulminant MH episode. The inhibitory potency of dantrolene on ECCE found in wild-type and MH-susceptible muscle is consistent with the drug's clinical potency for reversing the MH syndrome and is incomplete as predicted by its efficacy as a muscle relaxant.
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PMID:Enhanced excitation-coupled calcium entry in myotubes expressing malignant hyperthermia mutation R163C is attenuated by dantrolene. 1817 28

Though in the last few decades only a few new drugs have come available for the treatment of spasticity, new insights may revise the role and individual value of several pharmacological treatments. Diazepam, baclofen and tizanidine are the most prescribed drugs for the treatment of spasticity. Intrathecal baclofen and local infiltration of botulin toxin are added values in selective patients. Gabapentin is a novelty, and the working mechanism of cannabis has been elucidated. Dantrolene sodium appears to owe its selectivity from the recently discovered ryanodine receptor, with a peripheral effect in muscles. In this review the pathophysiology and epidemiology of spasticity, pharmacology, clinical efficacy and unwanted effects of the different drugs for spasticity are updated.
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PMID:Spasticity: revisiting the role and the individual value of several pharmacological treatments. 2087 Nov 49