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Electrophysiological characterization of spinal neuronal response properties in anaesthetized rats after ligation of spinal nerves L5-L6.
J Physiol. 1998 Mar 15; 507 (Pt 3):881-94.JP

Abstract

1. Despite a number of models of nerve injury, few studies have examined how peripheral nerve injury influences spinal somatosensory processing. 2. Ligation of two (L5-L6) of the three spinal nerves that form the sciatic nerve produces a partial denervation of the hindlimb. Following ligation, rats exhibited withdrawal responses to normally innocuous punctate mechanical and cooling stimuli (acetone) applied to the lesioned hindpaw. Such mechanical and cooling allodynia was not observed in sham-operated rats. 3. A significantly greater proportion of spinal neurones of ligated rats exhibited spontaneous activity at post-operative (PO) days 7-10 (P = 0.03) and 14-17 (P = 0.0001), compared with sham controls. The frequency of the spontaneous activity was significantly higher than that of the sham controls (P = 0.03 and P = 0.02 for days 7-10 and days 14-17, respectively). 4. At the earlier PO period, significantly (P = 0.02) more neurones of spinal nerve-ligated (SNL) rats responded to brush compared with the sham controls; at the later PO period the proportion of neurones of SNL rats responsive to prod was significantly (P = 0.007) reduced compared with the sham controls. The magnitude of the evoked neuronal response of SNL rats at PO days 7-10 was comparable to that of the sham controls. The magnitudes of brush- and prod-evoked neuronal responses of SNL rats were significantly smaller (P = 0.05 and P = 0.002, respectively) than the sham controls at PO days 14-17. In addition, neuronal responses of SNL rats to mechanical punctate stimuli and the C fibre-evoked neuronal responses were significantly reduced at the later PO period, compared with sham controls. Abeta-fibre-induced wind-up was not observed under any conditions. 5. These complex changes in neuronal responses are both time and modality dependent. The plasticity of some of the neuronal and behavioural responses following nerve injury was difficult to reconcile. We suggest that an interplay between pathological peripheral and central mechanisms may account for some of the changes that could contribute to allodynia and hyperalgesia.

Authors+Show Affiliations

Department of Pharmacology, University College London, Gower Street, London WC1E 6BT, UK. v.chapman@ucl.ac.ukNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9508847

Citation

Chapman, V, et al. "Electrophysiological Characterization of Spinal Neuronal Response Properties in Anaesthetized Rats After Ligation of Spinal Nerves L5-L6." The Journal of Physiology, vol. 507 (Pt 3), 1998, pp. 881-94.
Chapman V, Suzuki R, Dickenson AH. Electrophysiological characterization of spinal neuronal response properties in anaesthetized rats after ligation of spinal nerves L5-L6. J Physiol. 1998;507 (Pt 3):881-94.
Chapman, V., Suzuki, R., & Dickenson, A. H. (1998). Electrophysiological characterization of spinal neuronal response properties in anaesthetized rats after ligation of spinal nerves L5-L6. The Journal of Physiology, 507 (Pt 3), 881-94.
Chapman V, Suzuki R, Dickenson AH. Electrophysiological Characterization of Spinal Neuronal Response Properties in Anaesthetized Rats After Ligation of Spinal Nerves L5-L6. J Physiol. 1998 Mar 15;507 (Pt 3):881-94. PubMed PMID: 9508847.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Electrophysiological characterization of spinal neuronal response properties in anaesthetized rats after ligation of spinal nerves L5-L6. AU - Chapman,V, AU - Suzuki,R, AU - Dickenson,A H, PY - 1998/5/23/pubmed PY - 1998/5/23/medline PY - 1998/5/23/entrez SP - 881 EP - 94 JF - The Journal of physiology JO - J Physiol VL - 507 (Pt 3) N2 - 1. Despite a number of models of nerve injury, few studies have examined how peripheral nerve injury influences spinal somatosensory processing. 2. Ligation of two (L5-L6) of the three spinal nerves that form the sciatic nerve produces a partial denervation of the hindlimb. Following ligation, rats exhibited withdrawal responses to normally innocuous punctate mechanical and cooling stimuli (acetone) applied to the lesioned hindpaw. Such mechanical and cooling allodynia was not observed in sham-operated rats. 3. A significantly greater proportion of spinal neurones of ligated rats exhibited spontaneous activity at post-operative (PO) days 7-10 (P = 0.03) and 14-17 (P = 0.0001), compared with sham controls. The frequency of the spontaneous activity was significantly higher than that of the sham controls (P = 0.03 and P = 0.02 for days 7-10 and days 14-17, respectively). 4. At the earlier PO period, significantly (P = 0.02) more neurones of spinal nerve-ligated (SNL) rats responded to brush compared with the sham controls; at the later PO period the proportion of neurones of SNL rats responsive to prod was significantly (P = 0.007) reduced compared with the sham controls. The magnitude of the evoked neuronal response of SNL rats at PO days 7-10 was comparable to that of the sham controls. The magnitudes of brush- and prod-evoked neuronal responses of SNL rats were significantly smaller (P = 0.05 and P = 0.002, respectively) than the sham controls at PO days 14-17. In addition, neuronal responses of SNL rats to mechanical punctate stimuli and the C fibre-evoked neuronal responses were significantly reduced at the later PO period, compared with sham controls. Abeta-fibre-induced wind-up was not observed under any conditions. 5. These complex changes in neuronal responses are both time and modality dependent. The plasticity of some of the neuronal and behavioural responses following nerve injury was difficult to reconcile. We suggest that an interplay between pathological peripheral and central mechanisms may account for some of the changes that could contribute to allodynia and hyperalgesia. SN - 0022-3751 UR - https://www.unboundmedicine.com/medline/citation/9508847/Electrophysiological_characterization_of_spinal_neuronal_response_properties_in_anaesthetized_rats_after_ligation_of_spinal_nerves_L5_L6_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0022-3751&date=1998&volume=507&spage=881 DB - PRIME DP - Unbound Medicine ER -