Matches in SemOpenAlex for { <https://semopenalex.org/work/W2157179884> ?p ?o ?g. }
Showing items 1 to 79 of
79
with 100 items per page.
- W2157179884 abstract "It is now well known that axonal excitability properties are not identical in different human nerves. All human myelinated axons probably have similar resting membrane potential and outward rectifying potassium conductances, and share a common microstructure of nodes of Ranvier. However, there are significant differences in excitability and accommodative properties between sensory and motor axons (Bostock et al. 1994), between axons in the upper and lower limb nerves, between distal and proximal axons, and even between motor axons in the same nerve innervating different muscles (Bae et al. 2009). This is presumably because axonal properties are adapted to the pattern of impulse traffic normally carried by the axons.For example, sensory axons have more prominent persistent sodium channels that are open at rest (Bostock & Rothwell, 1997), and this explains why axonal firing threshold to electrical stimulation is always lower in sensory than in motor axons. Furthermore, inward rectifying conductances, usually driven in response to prolonged membrane hyperpolarization, appear to be expressed more on sensory axons than motor axons. Overall, excitability of sensory axons is physiologically higher than that of motor axons, leading to more ready development of ectopic activity (paraesthesiae or pain), and possibly to less susceptibility to nerve conduction block. Thus, the properties of different axons are not identical and their responses to injury or disease may therefore differ.In human motor axons, similar correlations of excitability properties with different responses to disease have been proposed. Fasciculation is a characteristic feature of amyotrophic lateral sclerosis (ALS). The ectopic firing of motor units usually arises from the motor nerve terminals, indicating a widespread abnormality in axonal excitability properties. So far, two kinds of axonal ion channel abnormalities have been found in ALS; increased persistent sodium currents, and reduced potassium currents, both increasing axonal excitability and responsible for generation of fasciculations (Kanai et al. 2006). The first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles are innervated by the same ulnar nerve, but studies have shown that the former is much more severely affected in ALS. This peculiar pattern of dissociated atrophy of the intrinsic hand muscles has been termed the ‘split hand’. Nodal persistent sodium conductances are much more prominent in FDI axons than in ADM axons, and the physiologically higher excitability could promote motor neuronal death in ALS (Bae et al. 2009). Previous excitability studies have focused on altered persistent sodium channels as major determinants of axonal excitability in motor neuron diseases and peripheral neuropathies.In a recent issue of The Journal of Physiology, the study by Trevillion et al. (2010) investigated the excitability and accommodative properties of low-threshold human median motor axons in healthy subjects. The authors, as well as many investigators, originally hypothesized that greater expression of persistent sodium channels on low-threshold axons could be the reason for the low threshold to electrical stimulation. However, their findings did not support a difference in persistent sodium conductance, and instead they nicely demonstrated greater activity of the hyperpolarization-activated inwardly rectifying current as the basis for low threshold to electrical recruitment. The results are somewhat surprising, but the provided data appear very convincing. The authors suggest that the inward rectifying channels expressed on human motor axons may be active at rest and contribute to resting membrane potential.The observation is novel, and could provide new insight into the pathophysiology in a variety of neurological disorders. Altered inward rectifying channels should be taken into consideration in the future researches on ALS and neuropathic pain. In ALS, in addition to altered sodium and potassium channels, it should be investigated whether inward rectification channels contribute to increased axonal excitability and thereby enhance motor neuronal death. Regarding neuropathic pain, as the authors cited, an experimental study using a nerve ligation model in the rat has shown that hyperpolarization-activated, cyclic nucleotide-modulated (HCN) channels play an important role in both pain and spontaneous neuronal discharge originating in the damaged dorsal root ganglion (Chaplan et al. 2003). HCN channels are abundantly expressed in rat primary afferent somata. Nerve injury markedly increases the currents in large-diameter dorsal root ganglion neurons and in spontaneous action potentials. Pharmacological blockade of HCN activity reverses abnormal hypersensitivity to light touch and decreases the firing frequency of ectopic discharges.Previous excitability studies rarely focused on HCN inward rectifying channels, the function of which can be reliably estimated by current–threshold relationships with computerized threshold tracking, as shown in the study by Trevillion et al. (2010). This relevant study raises the possibility that hyperpolarization-activated inward rectifying channels are active at rest, and directly affect membrane potential and thereby, axonal excitability. In future studies, HCN channels should be recognized as new targets for drug discovery in a variety of neurological disorders characterized by axonal hyperexcitability." @default.
- W2157179884 created "2016-06-24" @default.
- W2157179884 creator A5009588500 @default.
- W2157179884 date "2010-07-15" @default.
- W2157179884 modified "2023-09-25" @default.
- W2157179884 title "Inward rectifying channels as new targets for treatment" @default.
- W2157179884 cites W1497273779 @default.
- W2157179884 cites W2031422758 @default.
- W2157179884 cites W2046433440 @default.
- W2157179884 cites W2067285755 @default.
- W2157179884 cites W2118621245 @default.
- W2157179884 cites W2168774028 @default.
- W2157179884 doi "https://doi.org/10.1113/jphysiol.2010.193979" @default.
- W2157179884 hasPubMedCentralId "https://www.ncbi.nlm.nih.gov/pmc/articles/2916982" @default.
- W2157179884 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/20634181" @default.
- W2157179884 hasPublicationYear "2010" @default.
- W2157179884 type Work @default.
- W2157179884 sameAs 2157179884 @default.
- W2157179884 citedByCount "0" @default.
- W2157179884 crossrefType "journal-article" @default.
- W2157179884 hasAuthorship W2157179884A5009588500 @default.
- W2157179884 hasBestOaLocation W21571798842 @default.
- W2157179884 hasConcept C105702510 @default.
- W2157179884 hasConcept C131453863 @default.
- W2157179884 hasConcept C169760540 @default.
- W2157179884 hasConcept C178790620 @default.
- W2157179884 hasConcept C185592680 @default.
- W2157179884 hasConcept C24998067 @default.
- W2157179884 hasConcept C2775912687 @default.
- W2157179884 hasConcept C2778970341 @default.
- W2157179884 hasConcept C2779530196 @default.
- W2157179884 hasConcept C50952357 @default.
- W2157179884 hasConcept C537181965 @default.
- W2157179884 hasConcept C66974803 @default.
- W2157179884 hasConcept C86803240 @default.
- W2157179884 hasConcept C94487597 @default.
- W2157179884 hasConceptScore W2157179884C105702510 @default.
- W2157179884 hasConceptScore W2157179884C131453863 @default.
- W2157179884 hasConceptScore W2157179884C169760540 @default.
- W2157179884 hasConceptScore W2157179884C178790620 @default.
- W2157179884 hasConceptScore W2157179884C185592680 @default.
- W2157179884 hasConceptScore W2157179884C24998067 @default.
- W2157179884 hasConceptScore W2157179884C2775912687 @default.
- W2157179884 hasConceptScore W2157179884C2778970341 @default.
- W2157179884 hasConceptScore W2157179884C2779530196 @default.
- W2157179884 hasConceptScore W2157179884C50952357 @default.
- W2157179884 hasConceptScore W2157179884C537181965 @default.
- W2157179884 hasConceptScore W2157179884C66974803 @default.
- W2157179884 hasConceptScore W2157179884C86803240 @default.
- W2157179884 hasConceptScore W2157179884C94487597 @default.
- W2157179884 hasLocation W21571798841 @default.
- W2157179884 hasLocation W21571798842 @default.
- W2157179884 hasLocation W21571798843 @default.
- W2157179884 hasOpenAccess W2157179884 @default.
- W2157179884 hasPrimaryLocation W21571798841 @default.
- W2157179884 hasRelatedWork W1604355805 @default.
- W2157179884 hasRelatedWork W1606137504 @default.
- W2157179884 hasRelatedWork W1757430436 @default.
- W2157179884 hasRelatedWork W1817765156 @default.
- W2157179884 hasRelatedWork W2030994852 @default.
- W2157179884 hasRelatedWork W2035981380 @default.
- W2157179884 hasRelatedWork W2070403641 @default.
- W2157179884 hasRelatedWork W2071960060 @default.
- W2157179884 hasRelatedWork W2085252957 @default.
- W2157179884 hasRelatedWork W2102917688 @default.
- W2157179884 hasRelatedWork W2256788691 @default.
- W2157179884 hasRelatedWork W2261732011 @default.
- W2157179884 hasRelatedWork W2753892026 @default.
- W2157179884 hasRelatedWork W2756442034 @default.
- W2157179884 hasRelatedWork W2791458002 @default.
- W2157179884 hasRelatedWork W2945709311 @default.
- W2157179884 hasRelatedWork W2957971038 @default.
- W2157179884 hasRelatedWork W3118421748 @default.
- W2157179884 hasRelatedWork W339414464 @default.
- W2157179884 hasRelatedWork W69419588 @default.
- W2157179884 isParatext "false" @default.
- W2157179884 isRetracted "false" @default.
- W2157179884 magId "2157179884" @default.
- W2157179884 workType "article" @default.