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Sciatic nerve neuropathy target esterase. Methods of assay, proximo-distal distribution and regeneration
J B Barril1, E Vilanova, M C Pellin
1Departamento de Neuroquímica, Universidad de Alicante, Spain.
Abstract:
Some organophosphorus compounds (OP) induce a delayed polyneuropathy (OPIDP) which is initiated by the phosphorylation of the so-called neuropathy target esterase (NTE). In this work some aspects of hen sciatic nerve NTE are studied. The assay method is reported and modifications are discussed and a combined method proposed. Proximo-distal distribution showed a significant difference from proximal (100 +/- 10%) to distal (69 +/- 9%) fragments, in accordance with reported data. The time course of in vivo regeneration after a single TOCP dose (200 mg/kg, post oral) showed some differences when compared with hen brain NTE. Sciatic nerve NTE showed a delay of 2-3 days before regeneration but then regenerated faster (74% activity at day 7) than brain NTE (50% activity at day 7). A slower rate of regeneration of distal than proximal segments has been suggested to explain higher sensitivity of distal segments [3], however in this work no significant differences were observed in the rate of regeneration when comparing proximal and distal fragments.
Insights
Organophosphorus compounds cause delayed polyneuropathy by targeting neuropathy target esterase (NTE). This study details hen sciatic nerve NTE regeneration, showing faster recovery in nerves than the brain after exposure.
Area of Science:
- Neuroscience
- Toxicology
- Biochemistry
Background:
- Organophosphorus compounds (OP) can induce organophosphorus compound-induced delayed polyneuropathy (OPIDP).
- OPIDP is initiated by the phosphorylation of neuropathy target esterase (NTE).
- Understanding hen sciatic nerve NTE is crucial for OPIDP research.
Purpose of the Study:
- To investigate hen sciatic nerve neuropathy target esterase (NTE).
- To characterize the distribution and in vivo regeneration of NTE in hen sciatic nerves.
- To compare NTE regeneration in sciatic nerves versus brain tissue.
Main Methods:
- Development and discussion of an assay method for NTE.
- Analysis of proximo-distal distribution of NTE in hen sciatic nerve fragments.
- Monitoring of in vivo NTE activity regeneration following a single TOCP dose.
Main Results:
- Significant differences in NTE activity were observed between proximal and distal sciatic nerve fragments.
- Hen sciatic nerve NTE showed a 2-3 day delay in regeneration post-TOCP exposure.
- Sciatic nerve NTE regenerated faster than brain NTE, with 74% activity at day 7 compared to 50% for brain NTE.
Conclusions:
- Hen sciatic nerve NTE exhibits distinct distribution and regeneration kinetics compared to brain NTE.
- The observed regeneration patterns do not support the hypothesis of slower distal segment regeneration contributing to higher sensitivity.
- Further research into NTE's role in OPIDP is warranted.