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Updated: Aug 29, 2026

A Preterm Rat Model for Pain Studies
Published on: February 9, 2024
Strain differences in pain sensitivity and expression of preprodynorphin mRNA in rats following peripheral
Rui-Xin Zhang1, Lixing Lao, Jian-Tian Qiao
1Center for Integrative Medicine, School of Medicine, University of Maryland, Baltimore, MD 21201, USA. rzhan001@umaryland.edu
Abstract:
The experience of pain is highly variable among individuals, which may be due in part to the effects of genetic factors on the central transmission and modulation of noxious inputs. This study examined behavioral responses and the expression of preprodynorphin (PPD) mRNA at the spinal level during complete Freund's adjuvant-induced inflammation of the unilateral hind paw in male Fischer 344 (F344), Sprague-Dawley (SD), and Lewis (LEW) rats. Experiments showed that F344 rats exhibited stronger hind paw hyperalgesia and greater spinal PPD mRNA induction than SD or LEW rats. These results indicate that genetic factors that determine the spinal PPD mRNA and dynorphin production underlie strain-dependent differences in pain perception.

