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)

After chronic spinal cord injury motoneurons exhibit large plateau potentials (sustained depolarizations triggered by brief inputs) that play a primary role in the development of muscle spasms and spasticity (Bennett et al. 2001a,b). The present study examined the voltage-gated persistent inward currents (PICs) underlying these plateaus. Adult rats were spinalized at the S2 sacral spinal level and after 2 mo, when spasticity developed, intracellular recordings were made from motoneurons below the injury. For recording, the whole sacrocaudal spinal cord was removed and maintained in vitro in normal artificial cerebral spinal fluid (nACSF), without application of neuromodulators. During a slow triangular voltage-clamp command (ramp) a PIC was activated with a threshold of -54.2 +/- 4.8 mV (similar to plateau threshold), with a peak current of 2.88 +/- 0.95 nA and produced a pronounced negative-slope region in the V-I relation. This PIC was in part mediated by Cav1.3 L-type calcium channels because it was low threshold and significantly reduced by 10 to 20 microM nimodipine or 400 microM Cd2+. The PIC that remained during a calcium channel blockade (in Cd2+) was completely and rapidly blocked by tetrodotoxin (TTX; 0.5 to 2 microM), and thus was a TTX-sensitive persistent sodium current. This persistent sodium current was activated rapidly about 7 mV below the spike threshold (spike threshold -46.1 +/- 4.5 mV), contributed approximately 1/2 of the initial peak of the total PIC, inactivated partly to contribute only approximately 1/3 of the sustained PIC (at 5 to 10 s), and deactivated rapidly with hyperpolarization (<50 ms). When TTX was added to the bath first, the nimodipine-sensitive persistent calcium current (L-type) was seen in isolation; it was slowly activated (>250 ms), had a low but variable threshold (either slightly above or below the spike threshold), contributed the other approximately 1/2 of the initial peak of the total PIC (before TTX), did not usually inactivate with time (contributed approximately two-thirds of the sustained PIC), and deactivated slowly with hyperpolarization to rest (in >300 ms). In summary, low-threshold persistent calcium (Cav1.3) and sodium currents spontaneously develop in motoneurons of chronic spinal rats and these enable large, rapidly activated plateaus that ultimately lead to spasticity.
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PMID:Persistent sodium and calcium currents cause plateau potentials in motoneurons of chronic spinal rats. 1272 67

Medicinal Chemistry has played a critical role in evolving new products, resources and processes which inexorably correspond to our high standards of living. Unfortunately, this has also caused deterioration of human health and threats to the global environment, even deaths when highly exposed to certain chemicals, whether due to improper use, mishandling or disposal. There are chemicals, which apart from being carcinogens, endocrine disruptors or neurotoxins, are also responsible for climate change and ozone depletion. Certain chemicals are known to cause neurotoxicity and are having tendencies to damage the central and peripheral nervous system or brain by damaging neurons or cells which are responsible for transmitting and processing of signals. This has raised serious concerns for the use and handling of such chemicals and has given growth to a relatively new emerging field known as Green Chemistry that strives to achieve sustainability at the molecular level and has an ability to harness chemicals to meet environmental and economic goals. It has been reported in the literature that apart from family history in the aetiology of Amyotrophic lateral Sclerosis (ALS), also termed as "Lou Gehrig's disease", a neurological disorder, environmental factors, heavy metals, particularly selenium, lead, mercury, cadmium, formaldehyde, pesticides and certain herbicides are known to cause ALS. ALS, a progressive neurodegenerative disease affects the motor cortex, brain stem and spinal cord, causing muscular weakness, spasticity, and hyperreflexia. In this article we are aiming to discuss and summarize the various corroborations and findings supporting the undesirable role of chemical substance/herbicides/pesticides in ALS aetiology and its mitigation by adopting green chemistry.
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PMID:Denouement of Chemicals on Amyotrophic Lateral Sclerosis: Is Green Chemistry the Answer. 3228 7