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The prolonged analgesic effect of epidural ropivacaine in a rat model of neuropathic pain.
Anesth Analg. 2008 Jan; 106(1):313-20, table of contents.A&A

Abstract

BACKGROUND

In clinical practice, the analgesic effects of epidurally administered local anesthetics on chronic pain sometimes outlast the duration of drug action expected from their pharmacokinetics. To investigate the underlying mechanisms of this prolonged effect, we examined the effects of ropivacaine, a local anesthetic, on pain-related behavior in a rat model of neuropathic pain. We also analyzed changes in the expression of nerve growth factor (NGF), which is involved in plasticity of the nociceptive circuit after nerve injury.

METHODS

In a rat model of neuropathic pain produced by chronic constrictive injury (CCI) of the sciatic nerve, thermal hyperalgesia, and mechanical allodynia were observed from Day 3 after surgery. Ropivacaine or saline was administered through an epidural catheter once a day, every day, and from Days 7-13 after the CCI operation. NGF content was measured in the L4 dorsal root ganglion, the hindpaw skin, the L4/5 dorsal spinal cord, and the sciatic nerve, using enzyme immunoassay.

RESULTS

The latency to withdrawal from thermal stimuli on the ipsilateral paw pads of CCI rats was significantly increased 4 days after the beginning of ropivacaine treatment, and thermal hyperalgesia was almost fully relieved. Similarly, mechanical allodynia was partially reduced after ropivacaine treatment. NGF content was increased in the L4 dorsal root ganglion on the ipsilateral, but not the contralateral, side, in CCI rats treated with ropivacaine.

CONCLUSION

Repetitive administration of ropivacaine into the epidural space in CCI rats exerts an analgesic effect, possibly by inducing a plastic change in the nociceptive circuit.

Authors+Show Affiliations

Department of Pharmacology, Nippon Medical School, Tokyo, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

18165597

Citation

Sato, Chiyo, et al. "The Prolonged Analgesic Effect of Epidural Ropivacaine in a Rat Model of Neuropathic Pain." Anesthesia and Analgesia, vol. 106, no. 1, 2008, 313-20, table of contents.
Sato C, Sakai A, Ikeda Y, et al. The prolonged analgesic effect of epidural ropivacaine in a rat model of neuropathic pain. Anesth Analg. 2008;106(1):313-20, table of contents.
Sato, C., Sakai, A., Ikeda, Y., Suzuki, H., & Sakamoto, A. (2008). The prolonged analgesic effect of epidural ropivacaine in a rat model of neuropathic pain. Anesthesia and Analgesia, 106(1), 313-20, table of contents. https://doi.org/10.1213/01.ane.0000296460.91012.51
Sato C, et al. The Prolonged Analgesic Effect of Epidural Ropivacaine in a Rat Model of Neuropathic Pain. Anesth Analg. 2008;106(1):313-20, table of contents. PubMed PMID: 18165597.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The prolonged analgesic effect of epidural ropivacaine in a rat model of neuropathic pain. AU - Sato,Chiyo, AU - Sakai,Atsushi, AU - Ikeda,Yumiko, AU - Suzuki,Hidenori, AU - Sakamoto,Atsuhiro, PY - 2008/1/1/pubmed PY - 2008/10/23/medline PY - 2008/1/1/entrez SP - 313-20, table of contents JF - Anesthesia and analgesia JO - Anesth Analg VL - 106 IS - 1 N2 - BACKGROUND: In clinical practice, the analgesic effects of epidurally administered local anesthetics on chronic pain sometimes outlast the duration of drug action expected from their pharmacokinetics. To investigate the underlying mechanisms of this prolonged effect, we examined the effects of ropivacaine, a local anesthetic, on pain-related behavior in a rat model of neuropathic pain. We also analyzed changes in the expression of nerve growth factor (NGF), which is involved in plasticity of the nociceptive circuit after nerve injury. METHODS: In a rat model of neuropathic pain produced by chronic constrictive injury (CCI) of the sciatic nerve, thermal hyperalgesia, and mechanical allodynia were observed from Day 3 after surgery. Ropivacaine or saline was administered through an epidural catheter once a day, every day, and from Days 7-13 after the CCI operation. NGF content was measured in the L4 dorsal root ganglion, the hindpaw skin, the L4/5 dorsal spinal cord, and the sciatic nerve, using enzyme immunoassay. RESULTS: The latency to withdrawal from thermal stimuli on the ipsilateral paw pads of CCI rats was significantly increased 4 days after the beginning of ropivacaine treatment, and thermal hyperalgesia was almost fully relieved. Similarly, mechanical allodynia was partially reduced after ropivacaine treatment. NGF content was increased in the L4 dorsal root ganglion on the ipsilateral, but not the contralateral, side, in CCI rats treated with ropivacaine. CONCLUSION: Repetitive administration of ropivacaine into the epidural space in CCI rats exerts an analgesic effect, possibly by inducing a plastic change in the nociceptive circuit. SN - 1526-7598 UR - https://www.unboundmedicine.com/medline/citation/18165597/The_prolonged_analgesic_effect_of_epidural_ropivacaine_in_a_rat_model_of_neuropathic_pain_ L2 - https://doi.org/10.1213/01.ane.0000296460.91012.51 DB - PRIME DP - Unbound Medicine ER -