A rat model of postthoracotomy pain: behavioural and spinal cord NK-1 receptor assessment

Citation
T. Nara et al., A rat model of postthoracotomy pain: behavioural and spinal cord NK-1 receptor assessment, CAN J ANAES, 48(7), 2001, pp. 665-676
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Aneshtesia & Intensive Care","Medical Research Diagnosis & Treatment
Journal title
CANADIAN JOURNAL OF ANAESTHESIA-JOURNAL CANADIEN D ANESTHESIE
ISSN journal
0832-610X → ACNP
Volume
48
Issue
7
Year of publication
2001
Pages
665 - 676
Database
ISI
SICI code
0832-610X(200107/08)48:7<665:ARMOPP>2.0.ZU;2-6
Abstract
Purpose: To develop a new rat model of postthoracotomy pain for investigati ng its mechanisms and clarifying neurochemical changes. Methods: Male Wistar rats were randomly assigned to three groups that under went either fourth and fifth intercostal nerve ligation, cutting of the fou rth and fifth ribs, or a sham operation in which only pleura was cut. For b ehavioural response assessment during the following month, pinch and touch were used as mechanical stimuli, and acetone was used as a cold thermal sti mulus. in addition, I-125-substance P autoradiography was used to determine neurokinin (NK) receptor density in spinal cord laminae I and II at one to six weeks after surgery. Results: In rats with nerve ligation, hypersensitivity to noxious and non-n oxious stimuli continued throughout the month. The "mirror phenomenon" was observed. The lowest threshold was obtained in the dorsomedial portion of t he T4 dermatome on the side of surgery. In rats with rib cutting, a lowered threshold to noxious and non-noxious stimuli was observed for two weeks. I n rats with sham operations, hypersensitivity was seen only at postoperativ e day one. NK-I receptor density on the side of operation increased signifi cantly in rats with nerve ligation from day seven to 28. Receptor density w as highest on day 14 (22.97 +/- 1.04 fmol(.)mg(-1) tissue vs control, 16.22 +/- 0.43), representing a 50% receptor excess on the side of ligation comp ared to the contralateral side. Conclusion: Intercostal nerve damage induces long-term postthoracotomy pain and an increase of spinal NK-I receptors in rats. This model may be useful for investigation of postthoracotomy pain.