Substance P, NK1, and NMDA receptor 1 increase in spinal cord dorsal horns in a rat model of repetitive motion injury

Details

• Personal Author:
  Amin M ; Barbe MF ; Barr AE ; Elliott MB ; Fedorcyzk J
• Description:
  Recent studies in patients have identified the presence of neurochemicals, such as Substance P, in forelimb tendons in association with chronic tennis elbow. Our lab has developed a rat model of upper extremity repetitive motion injury. Recently, we found that performance of this task resulted in increased levels of Substance P and NMDAr1 in flexor forelimb tendons. In the present study, we investigated neurochemical changes in spinal cords following 10 weeks of either a high repetition high force (HRHF), a high repetition low force (HRLF), or a low repetition low force (LRLF) task. A total of 46 Sprague-Dawley rats were used: 12 performed the HRLF task, 12 performed the HRHF task, 12 performed the LRLF tasks, and 10 were controls. For the HRLF and LRLF tasks, rats reached and retrieved a 45 mg food pellet at a target reach rate of 4 reaches/min (HRLF), or 2 reaches/min (LRLF). For the HRHF task, rats grasped and pulled on a handle at a target force level of 60% maximum grip force, and at a target reach rate of 4 reaches/min. This task was performed in 4, 0.5 hour sessions separated by 1.5 hours for 3 days/week for periods of up to 10 weeks. For histological analysis, animals were euthanized using Nembutol (120 mg/kg body weight) and perfused with 4% paraformaldehyde in 0.1M phosphate buffer (pH= 7.4). Spinal cords were collected, frozen sectioned and examined immunohistochemically for Substance P, Neurokinin 1, and NMDAr1. In the HRLF and HRHF rats, Substance P, NK1 and NMDAr1 were significantly increased in laminae I and II of cervical segments of the spinal cord in dorsal horns ipsilateral to the reach limb compared to LRLF and control rats. This increase in a spinal cord neuropeptide and its receptors correlate with findings of peripheral tissue inflammation in the forearm, as well as increases in peripheral tissue Substance P levels. This increased neurochemical response centrally may be linked to persistent chronic pain associated with repetitive motion injuries. [Description provided by NIOSH]
• Subjects:
  Aging Animals Behavior Cumulative Trauma Disorders Laboratories Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Age-groups Bone-structure Cumulative-trauma Cumulative-trauma-disorders Force Injuries Laboratory-animals Models Musculoskeletal-system Musculoskeletal-system-disorders Repetitive-work Tissue-culture

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• Document Type:
  Text
• Funding:
  Cooperative Agreement
• Genre:
  Abstract or Summary
• Place as Subject:
  Georgia ; OSHA Region 3 ; OSHA Region 4 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20041727
• Citation:
  Neuroscience 2006, October 14-18, 2006, Atlanta, Georgia. Washington, DC: Society for Neuroscience, 2006 Oct; :738.21/P14
• Federal Fiscal Year:
  2007
• Performing Organization:
  Temple University, Philadelphia, Pennsylvania
• Peer Reviewed:
  False
• Start Date:
  20050701
• Source Full Name:
  Neuroscience 2006, October 14-18, 2006, Atlanta, Georgia
• End Date:
  20080630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4fe32de627d80b3af4bde079155ae79086b2b5025148817a3130b1071b0073d1c1eccb83d431ef7adf2c9b23ad259568ef622e30b47f592088dbd3bb280913eb
• Download URL:
  https://stacks.cdc.gov/view/cdc/194214/cdc_194214_DS1.pdf
• File Type:
  [PDF - 328.80 KB ]