Conditioned place preference and spontaneous dorsal horn neuron activity in chronic constriction injury model in rats

Brian D Dalm; Chandan G Reddy; Matthew A Howard; Sinyoung Kang; Timothy J Brennan

doi:10.1097/j.pain.0000000000000365

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Conditioned place preference and spontaneous dorsal horn neuron activity in chronic constriction injury model in rats

Journal article

Peer reviewed

Conditioned place preference and spontaneous dorsal horn neuron activity in chronic constriction injury model in rats

Brian D Dalm, Chandan G Reddy, Matthew A Howard, Sinyoung Kang and Timothy J Brennan

Pain (Amsterdam), Vol.156(12), pp.2562-2571

12/2015

DOI: 10.1097/j.pain.0000000000000365

PMCID: PMC4715376

PMID: 26584420

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Abstract

Patients with neuropathic pain commonly present with spontaneous pain, in addition to allodynia and hyperalgesia. Although evoked responses in neuropathic pain models are well characterized, determining the presence of spontaneous pain is more challenging. We determined whether the chronic constriction injury (CCI) model could be used to measure effects of treatment of spontaneous pain, by evaluating dorsal horn neuron (DHN) spontaneous activity and spontaneous pain-related behaviors. We measured conditioned place preference (CPP) to analgesia produced by sciatic nerve block with bupivacaine in rats with established CCI. We undertook another CPP experiment using hind paw incision. We also examined DHN spontaneous activity in CCI rats. Although CCI produced nocifensive responses to mechanical stimuli, CPP to analgesic nerve block was not evident 14 days after injury: Compared with baseline (314 ± 65 seconds), CCI rats did not show a preference for the bupivacaine-paired chamber after conditioning (330 ± 102 seconds). However, sciatic nerve block after hind paw incision produced CPP on postoperative day 1, serving as a positive control. The proportion of spontaneously active DHNs (33%) was not significantly increased in CCI rats compared with the sham (21%). The median rate of spontaneous activity in the CCI group (12.6 impulses per second) was not different from the sham group (9.2 impulses per second). Also, there was no change in DHN spontaneous activity after sciatic nerve block with bupivacaine. Our findings suggest that CCI as a neuropathic pain model should not be used to measure effects of treatment of spontaneous pain driven by the peripheral input.

Sciatic Nerve - injuries

Nerve Block

Rats

Male

Rats, Sprague-Dawley

Hyperalgesia - physiopathology

Behavior, Animal

Animals

Bupivacaine

Ligation

Conditioning (Psychology)

Foot Injuries - physiopathology

Neuralgia - physiopathology

Posterior Horn Cells - physiology

Anesthetics, Local

Disease Models, Animal

Details

Title: Subtitle: Conditioned place preference and spontaneous dorsal horn neuron activity in chronic constriction injury model in rats
Creators: Brian D Dalm - Departments of aNeurosurgery bAnesthesia and cPharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
Chandan G Reddy
Matthew A Howard
Sinyoung Kang
Timothy J Brennan
Resource Type: Journal article
Publication Details: Pain (Amsterdam), Vol.156(12), pp.2562-2571
DOI: 10.1097/j.pain.0000000000000365
PMID: 26584420
PMCID: PMC4715376
NLM abbreviation: Pain
ISSN: 0304-3959
eISSN: 1872-6623
Publisher: United States
Grant note: T32 NS045549 / NINDS NIH HHS
Language: English
Date published: 12/2015
Academic Unit: Neurology; Iowa Neuroscience Institute; Anesthesia; Neurosurgery; Otolaryngology
Record Identifier: 9984007296402771

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