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

Most MS patients use unconventional therapies, usually as complementary measures in addition to the conventional treatment. Only a few adequate clinical trials exist in this field. By definition, the efficacy of these therapies is unproven. Moreover, the possible risks are also largely unknown. Some therapies rely on rational pathophysiological considerations, other must be regarded as potentially harmful. The influence of diet on MS is unproven. Possibly, unsaturated fatty acids are beneficial. However, a few randomized trials yielded inconclusive results. Long-term supplementation of Vitamin D is associated with a decreased MS incidence. There is, however, insufficient evidence for an influence of Vitamin D on the course of the disease. Because of the high prevalence of osteoporosis in MS patients, prophylaxis with Vitamin D and Calcium is widely accepted. The effects of various minerals, selenium, antioxidant compounds, fish oil or vitamins remain speculative. Many patients use cannabis to alleviate spasticity and pain. Small series indicated positive effects, but randomized trials were negative for spasticity. However, many patients report subjective improvement under cannabis even if their objective parameters remain unchanged. Hyperbaric oxygenation was the subject of several small studies with heterogeneous results which, overall, do not support its use. Generally, physical therapies are perceived as an established therapy for MS. Short-term effects are probable, whereas the possible favourable long-term effects are unclear.
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PMID:[Alternative and complementary therapies in multiple sclerosis]. 1605 39

Osteoporosis is a known consequence of spinal cord injury (SCI) and occurs in almost every SCI patient. It manifests itself as an increase in the incidence of lower extremity fractures. The pattern of bone loss seen in SCI patients is different from that usually encountered with endocrine disorders and disuse osteoporosis. In general, there is no demineralization in supralesional areas following SCI. Several factors appear to have a major influence on bone mass in SCI individuals, such as the degree of the injury, muscle spasticity, age, sex and duration after injury. At the lumbar spine, bone demineralization remains relatively low compared to that of the long bones in the sublesional area. A new steady state level between bone resorption and formation is reestablished about 2 years after SCI. SCI may not only cause bone loss, but also alter bone structure and microstructure. Trabecular bone is more affected than cortical bone in the SCI population. Numerous clinical series have reported a high incidence ranging from 1 to 34% of lower extremity fractures in SCI patients. The pathogenesis of osteoporosis after SCI remains complex and perplexing. Disuse may play an important role in the pathogenesis of osteoporosis, but neural factors also appear to be important. SCI also leads to impaired calcium and phosphate metabolism and the parathyroid hormone (PTH)-vitamin D axis. Pharmacologic intervention for osteoporosis after SCI includes calcium, phosphate, vitamin D, calcitonin and biphosphonates. However, the concomitant prescription of bone-active drugs for the prevention and treatment of osteoporosis remains low, despite the availability of effective therapies. Functional stimulated exercises may contribute to the prevention of bone loss to some extent. In addition, many unanswered questions remain about the pathogenesis of osteoporosis and its clinical management.
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PMID:Osteoporosis after spinal cord injury. 1621 89

Metabotropic gamma-aminobutyric acid(B) (GABAB) receptors for the major inhibitory transmitter GABA, together with metabotropic glutamate (mGLuRs) receptors, the extracellular calcium-sensing receptors (CaSRs), some V2R pheromone receptors and T1R taste receptors, belong to the family of 3 G-protein-coupled receptors (GPCRs). GABAB receptors are known to control neuronal excitability and modulate synaptic neurotransmission, playing a very important role in many physiological activities. These receptors are widely expressed and distributed in the nervous system and have been implicated in a variety of neurodegenerative and pathophysiological disorders including epilepsy, spasticity, chronic pain, depression, schizophrenia and drug addiction. To form a functional receptor entity, GABAB receptors must exist as a heterodimer consisting of GABAB1 and GABAB2 receptor subtypes with two 7-transmembrane proteins, and these subunits arise from distinct genes. The GABAB1 subunit binds the endogenous ligand within its extracellular N-terminus, whilst the GABAB2 subunit is not only essential for the correct trafficking of the GABAB1 subunit to the cell surface, but is also responsible for the interaction of the receptor with its cognate G-protein. Allosteric modulation has recently been recognized as an alternative pharmacological approach to gain selectivity in drug action. It is now generally accepted that modulators acting at the allosteric sites provide a novel perspective for the development of subtype-selective agents acting at GPCRs. These agents interact with allosteric binding sites quite separate from the highly conserved agonist binding region. In this review, we present a new class of phenylalkylamines, based on the lead compound fendiline, that are potent positive potentiators of GABAB receptor-mediated function and discuss their putative clinical applications. It is proposed that these new modulators may have therapeutic value in GABAB receptor pharmacology and are capable of selectively modifying GABAB receptor function. The allosteric modulators are offering an attractive and novel means to identify new leads, that are devoid of side effects associated with GABAB receptor agonists, and may, therefore, represent a major advance in the drug discovery process.
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PMID:Clinical potential of GABAB receptor modulators. 1638 96

Antiepileptic drugs (AEDs) affect various neurotransmitters (i.e. GABA, glutamate), receptors (i.e. GABAergic, glutamatergic), and ion channels (i.e. for sodium or calcium) which is responsible for their anticonvulsant activity. However, this broad spectrum of action may be also utilized in other pathological conditions. For example, both conventional and newer AEDs may be used in patients suffering from neuropathic pain, migraine, essential tremor, spasticity, restless legs syndrome and a number of psychiatric disorders (f.e. bipolar disease or schizophrenia). Also, isolated data point to their potential use in Parkinson's or Alzheimer's disease. There is experimental background indicating a potent neuroprotective efficacy of AEDs in numerous models of brain ischemia. However, the clinical data are very limited and this problem requires careful assessment.
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PMID:Non-epilepsy uses of antiepilepsy drugs. 1653 24

We examined the modulation of persistent inward currents (PICs) by serotonin (5-HT) in spinal motoneurons of normal and chronic spinal rats. PICs are composed of both a TTX-sensitive persistent sodium current (Na PIC) and a nimodipine-sensitive persistent calcium current (Ca PIC), and we focused on quantifying the Na PIC (and its action on the total PIC), which is known to be critical in enabling repetitive firing. Intracellular recordings were made from motoneurons of the whole sacrocaudal spinal cord of normal adult rats after the cord was acutely transected at the S2 spinal level (acute spinal rat condition), removed from the animal, and then maintained in vitro. In vitro motoneuron recordings were likewise made from rats that had a sacral spinal transection 2 mo previously (chronic spinal rats). In motoneurons from acute spinal rats, moderately high doses of 5-HT (> or = 10 microM), or the 5-HT2 receptor agonist DOI (> or = 30 microM), significantly increased the total PIC, hyperpolarized the PIC onset voltage, and hyperpolarized the spike threshold, whereas lower doses had no effect. Both 5-HT and DOI specifically increased the Na PIC portion of the total PIC (tested with nimodipine blocking the Ca PIC). Additionally, 5-HT, but not DOI, depolarized the resting membrane potential (Vm) and increased the input resistance (Rm) in a dose-dependent manner. Therefore 5-HT2 receptor activation facilitated the Na PIC, whereas other 5-HT receptors modulated Vm and Rm. Motoneurons of chronic spinal rats responded to 5-HT and DOI in the same way, but with larger responses and at much lower doses (0.3-1 microM), thus exhibiting a 30-fold supersensitivity to 5-HT. Specifically the Na PIC was supersensitive to 5-HT2 receptor activation with DOI. Also, Rm and Vm were supersensitive to 5-HT. Consistent with the known critical role of the Na PIC in repetitive firing, enhancement of the Na PIC by DOI or 5-HT facilitated the repetitive firing evoked by steady current injection and enabled repetitive firing in a subpopulation of motoneurons of acute spinal rats that were initially unable to produce sustained repetitive firing. We suggest that after spinal transection, residual endogenous spinal sources of 5-HT help facilitate the Na PIC and repetitive firing. With chronic injury, the developed 5-HT supersensitivity more than compensates for lost brain stem 5-HT, so that the Na PIC is large and motoneurons are very excitable, thus contributing to spasticity.
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PMID:5-HT2 receptor activation facilitates a persistent sodium current and repetitive firing in spinal motoneurons of rats with and without chronic spinal cord injury. 1670 14

In the months after spinal cord transection, motoneurons in the rat spinal cord develop large persistent inward currents (PICs) that are responsible for muscle spasticity. These PICs are mediated by low-threshold TTX-sensitive sodium currents (Na PIC) and L-type calcium currents (Ca PIC). Recently, the Na PIC was shown to become supersensitive to serotonin (5-HT) after chronic injury. In the present paper, a similar change in the sensitivity of the Ca PIC to 5-HT was investigated after injury. The whole sacrocaudal spinal cord from acute spinal rats and spastic chronic spinal rats (S2 level transection 2 mo previously) was studied in vitro. Intracellular recordings were made from motoneurons and slow voltages ramps were applied to measure PICs. TTX was used to block the Na PIC. For motoneurons of chronic spinal rats, a low dose of 5-HT (1 microM) significantly lowered the threshold of the Ca PIC from -56.7 +/- 6.0 to -63.1 +/- 7.1 mV and increased the amplitude of the Ca PIC from 2.4 +/- 1.0 to 3.0 +/- 0.73 nA. Higher doses of 5-HT acted similarly. For motoneurons of acute spinal rats, low doses of 5-HT had no significant effects, whereas a high dose (about 30 microM) significantly lowered the threshold of the L-Ca PIC from -58.5 +/- 14.8 to -62.5 +/- 3.6 mV and increased the amplitude of the Ca PIC from 0.69 +/- 1.05 to 1.27 +/- 1.1 nA. Thus Ca PICs in motoneurons are about 30-fold supersensitive to 5-HT in chronic spinal rats. The 5-HT-induced facilitation of the Ca PIC was blocked by nimodipine, not by the I(h) current blocker Cs(+) (3 mM) or the SK current blocker apamin (0.15 microM), and it lasted for hours after the removal of 5-HT from the nCSF, even increasing initially after removing 5-HT. The effects of 5-HT make motoneurons more excitable and ultimately lead to larger, more easily activated plateaus and self-sustained firing. The supersensitivity to 5-HT suggests the small amounts of endogenous 5-HT below the injury in a chronic spinal rat may act on supersensitive receptors to produce large Ca PICs and ultimately enable muscle spasms.
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PMID:Serotonin facilitates a persistent calcium current in motoneurons of rats with and without chronic spinal cord injury. 1707 37

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

Adjuvant analgesics are drugs that are not primarily used as analgesics but can produce analgesia in certain types of pain. Adjuvant analgesics can be administered together with non-opioid and opioid analgesics on each step of the WHO analgesic ladder. They should be given when an additional or specific indication exists, but should not be used as a substitute for a thorough treatment with opioids and nonopioids. Adjuvant analgesics can be classified into groups according to the type of pain to be treated: continuous neuropathic pain or lancinating neuropathic pain, sympathetically maintained pain, bone pain and those for multipurpose use. Adjuvant drugs used for continuous neuropathic pain include local anaesthetics, clonidine, capsaicin, and antidepressants. Tricyclic antidepressants are the group that have been best investigated, and are therefore the drugs of choice. An analgesic effect is probably produced via enhancement of transmitter concentrations in pain-modulating pathways. This occurs at lower doses than those necessary to treat depression. Anticholinergic actions, acute glaucoma, constipation, orthostatic hypotension and cardiac arrhythmias are adverse effects that are seen predominantly with teritiary amine drugs and less often with secondary amine compounds. Initial doses should be small to avoid these adverse effects. Local anaesthetics are used less often, because of the high incidence of side effects (especially with tocainide, flecainide). An analgesic effect has been described in neuropathic pain, however, probably due to membrane stabilization and reduction of aberrant signal conduction. Mexiletine is considered to be the safest local anaesthetic, and should be used initially in small doses (100-150 mg/d). If side effects do not occur, doses can be increased step-wise up to 900 mg/d. Local anaesthetics are indicated for the treatment of severe neuropathic pain; this treatment is contraindicated in patients with cardiac arrhythmias. Systemic or intrathecal clonidine can be tried in neuropathic pain refractory to opioid therapy. The same stands for the topical application of capsaicin in certain types of pain. Lancinating neuropathic pain is an indication for anticonvulsant drugs. Carbamazepine, clonazepam, valproate and phenytoin seem to reduce aberrant signal conduction in damaged nerves in a manner similar to the supression of epileptiform activities in the brain. Common side effects include sedation, dizziness and nausea. Of greater concern are the more severe side effects, such as bone marrow depression (carbamazepine) and hepatotoxicity (phenytoin, valproate). Low initial doses and stepwise increases in dosage, repeated blood counts, and monitoring of plasma levels are helpful in recognizing and avoiding these adverse effects. Baclofen, a GABA agonist primarily used for spasticity, is effective in the treatment of trigeminal neuralgia and is often used in the management of lancinating pain of unspecific origin. The initial dosage is 10-15 mg/d, increasing to 30-90 mg/d, or higher. If neural blockade fails to reduce sympathetically maintained pain sufficiently specific adjuvants can be used. Sympatholytic drugs, e.g. phenoxybenzamine (60-120 mg/d) or prazosin, can be administered to patients without major cardiovascular dysfunction. There is experimental evidence of the involvement of calcium channels in nociception, and a beneficial clinical effect of nifidepine in reflex sympathetic dystrophy (RDS) has been demonstrated. Bone pain is common in tumor patients and can often be treated effectively with non-steroidal anti-inflammatory drugs. Biphosphonates (etidronate, clodronate, pamidronate derivates) also produce analgesic effects in patients with bone metastases. However, differences among the various compounds have not been clearly evaluated yet. Potent and specific radioisotopes are still under development and the use of calcitonin in bone pain is considered controversial.
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PMID:[Pharmacotherapy of cancer pain. 3. Adjuvant drugs.]. 1841 35

Tumoral calcinosis (TC), a calcium hydroxyapatite-based mass, is common in the extremities and hips, but has rarely been reported in the spine, and has never been reported within the spinal cord. It may occur sporadically, in familial form, or as a consequence of disorders that promote soft-tissue calcification. Gross-total resection appears to be curative, but the diagnosis of TC is rarely considered prior to surgery. In this report, the authors describe the management of the first case of intramedullary TC located at the T-5 level in a 20-month-old boy who presented with lower-extremity spasticity. Additionally, salient features of the TC diagnosis, radiological patterns, histological findings, treatment, and outcomes are discussed.
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PMID:Intramedullary tumoral calcinosis. 2051 39

Hereditary spastic paraplegias (HSPs) are a group of neurological disorders characterized clinically by spasticity of lower limbs and pathologically by degeneration of the corticospinal tract. Troyer syndrome is an autosomal recessive HSP caused by a frameshift mutation in the spartin (SPG20) gene. Previously, we established that this mutation results in a lack of expression of the truncated mutant spartin protein. Spartin is involved in many cellular processes and associates with several intracellular organelles, including mitochondria. Spartin contains a conserved plant-related senescence domain at its C-terminus. However, neither the function of this domain nor the roles of spartin in mitochondrial physiology are currently known. In this study, we determined that the plant-related senescence domain of spartin interacts with cardiolipin but not with two other major mitochondrial phospholipids, phosphatidylcholine and phosphatidylethanolamine. We also found that knockdown of spartin by small interfering RNA in a human neuroblastoma cell line resulted in depolarization of the mitochondrial membrane. In addition, depletion of spartin resulted in a significant decrease in both mitochondrial calcium uptake and mitochondrial membrane potential in cells treated with thapsigargin. Our results suggest that impairment of mitochondrial calcium uptake might contribute to the neurodegeneration of long corticospinal axons and the pathophysiology of Troyer syndrome.
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PMID:SPG20 protein spartin associates with cardiolipin via its plant-related senescence domain and regulates mitochondrial Ca2+ homeostasis. 2155 43


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