Effect of aging on the substance P receptor, NK–1, in the spinal cord of rats with peripheral nerve injury.

Title

Effect of aging on the substance P receptor, NK–1, in the spinal cord of rats with peripheral nerve injury.

Creator

Cruce William L R; Lovell John A; Crisp Terriann; Stuesse Sherry L

Publisher

Somatosensory & Motor Research

Date

2001
2001-01-16

Description

Substance P (SP) levels in the spinal cords of very old rats are less than the levels in younger rats (Bergman et al., 1996). After injury to a peripheral nerve in young rats, immunoreactivity (ir) to the SP receptor, NK-1 (neurokinin-1), increases in the spinal cord ipsilateral to the injury and the increases are correlated with the development of thermal hyperalgesia (Goff et al., 1998). Thus we postulated that aged rats might display an increased sensitivity to thermal stimulation before peripheral nerve injury and that they might respond differently to injury than do younger rats. To test this hypothesis, we used the Bennett and Xie model (1988) of chronic constriction injury (CCI) to the sciatic nerve to induce a neuropathic pain condition. We investigated the effect of age on changes in NK-1 ir in superficial layers of the dorsal horn and on numbers of NK ir cells in deeper laminae at the L4-L5 levels of the spinal cord after CCI. NK-1 receptors were tagged immunohistochemically and their distribution quantified by use of computer-assisted image analysis. NK-1 ir changes were related to alterations in thermal and tactile sensitivity that developed after CCI in young, mature and aged (4-6, 14-16, and 24-26 months) Fischer F344 BNF1 hybrid rats. No differences in thermal or tactile sensitivity of young and aged rats were seen in the absence of nerve injury. After injury, aged rats developed thermal hyperalgesia and tactile allodynia more slowly than did the younger rats. NK-1 receptor ir and numbers of NK-1 ir cells in the dorsal horn increased with time post-injury in all three groups. NK-1 ir increases were correlated with the development of thermal hyperalgesia in those rats that displayed hyperalgesia. However, some rats developed an increased threshold to thermal stimuli (analgesia) and that also was correlated with increases in NK-1 ir. Thus NK-1 ir extent, while correlated with thermal sensitivity in the absence of injury, is not a specific marker for disturbances in one particular sensory modality; rather it increases with peripheral nerve injury per se. [ABSTRACT FROM AUTHOR]

Subject

ANIMAL models for aging; INJURIES to the peripheral nervous system; SPINAL cord injuries; SUBSTANCE P

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

66–75

Issue

1

Volume

18

Citation

Cruce William L R; Lovell John A; Crisp Terriann; Stuesse Sherry L, “Effect of aging on the substance P receptor, NK–1, in the spinal cord of rats with peripheral nerve injury.,” NEOMED Bibliography Database, accessed November 28, 2022, https://neomed.omeka.net/items/show/5773.

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