Pain Medicine  |   August 2017
Assessment of Behavioral Disruption in Rats with Abdominal Inflammation Using Visual Cue Titration and the Five-choice Serial-reaction Time Task
Author Notes
  • From the Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, North Carolina.
  • This article is featured in “This Month in Anesthesiology,” page 1A.
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    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
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  • Submitted for publication October 31, 2016. Accepted for publication April 26, 2017.
    Submitted for publication October 31, 2016. Accepted for publication April 26, 2017.×
  • Address correspondence to Dr. Martin: Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157. tjmartin@wakehealth.edu. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Pain Medicine / Basic Science / Pain Medicine
Pain Medicine   |   August 2017
Assessment of Behavioral Disruption in Rats with Abdominal Inflammation Using Visual Cue Titration and the Five-choice Serial-reaction Time Task
Anesthesiology 8 2017, Vol.127, 372-381. doi:10.1097/ALN.0000000000001702
Anesthesiology 8 2017, Vol.127, 372-381. doi:10.1097/ALN.0000000000001702
Abstract

Background: Both acute and chronic pain result in a number of behavioral symptoms in patients, including cognitive effects such as decreased attention and working memory. Intraperitoneal administration of dilute lactic acid in rodents has been used to induce abdominal inflammation and produce effects in behavioral assays of both sensory-discriminative and affective pain modalities.

Methods: Intraperitoneal injection of dilute lactic acid was used to study the impact of abdominal inflammation on an operant task requiring sustained visual attention in rats (N = 7 to 15/group) that adapts dynamically to performance ability. The effects of ketoprofen and morphine on lactic acid–induced impairment were compared with those on the disruptive effects of scopolamine.

Results: Lactic acid impaired performance in a concentration-dependent manner, increasing the duration of cue presentation required to maintain optimal performance from 0.5 ± 0.2 s (mean ± SD) to 17.2 ± 11.4 s after the administration of 1.8% (v/v) (N = 13). The latency to emit correct responses and to retrieve the food reward were both increased by lactic acid. All effects of lactic acid injection were reversed by both ketoprofen and morphine in a dose-dependent manner. Scopolamine, however, produced dose-dependent, nonpain-related disruption in sustained attention that was not altered by either ketoprofen or morphine.

Conclusions: These data demonstrate that abdominal inflammation induced by lactic acid produces robust disruption in a visual attention-based operant task and that this disruption is reversed by analgesics. Future studies will focus on pain-related circuitry and its impact on both limbic forebrain and frontal cortical mechanisms.