Somatosensory Systems, PainStrain differences in adrenergic sensitivity of neuropathic pain behaviors in an experimental rat modelLee, Doo Hyun1; Chung, Kyungsoon1,2; Chung, Jin Mo1,2,3,4Author Information 1Marine Biomedical Institute, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1069, USA 2Departments of Anatomy and Neurosciences, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1069, USA 3Physiology and Biophysics, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1069, USA 4Corresponding Author and Address: Jin Mo Chung, Marine Biomedical Institute, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1069, USA Received 21 August 1997; accepted 2 September NeuroReport: November 10th, 1997 - Volume 8 - Issue 16 - p 3453-3456 Buy Abstract THE aim of this study was to examine and delineate the differences in adrenergic sensitivity of mechanical allodynic behavior among various strains of rats. Neuropathic injury was produced by tight ligation of the L5 and L6 spinal nerves in several strains of rats. The degree of mechanical allodynic behavior was estimated by measuring the mechanical threshold for paw flinching with von Frey filaments. Adrenergic sensitivity of the allodynic behavior was resolved by measuring changes of the mechanical threshold after intraperitoneal injection of phentolamine, an α-adrenergic receptor antagonist. Injection of phentolamine caused a significant but small increase in the thresholds for paw flinching in rats of most of the tested strains; however, in Lewis rats, the resulting threshold increase was extensive enough to eliminate allodynic behavior almost completely. It is concluded that there is a difference in adrenergic sensitivity to mechanical allodynic behavior among different strains of neuropathic rats. In particular, rats of the Lewis strain were extremely sensitive to systemic injection of an α-adrenergic receptor blocker. © Lippincott-Raven Publishers.