Effects of MK-801 and Morphine on Spinal C-Fos Expression during the Development of Neuropathic Pain
Yonsei Medical Journal
;
: 370-376, 2002.
Article
in English
| WPRIM
| ID: wpr-84792
ABSTRACT
The purpose of this study was to investigate the expression of c-fos in the spinal cord during the development of allodynia, induced by peripheral nerve injury. Following tight ligation of the left L5 and L6 spinal nerves of Sprague- Dawley rat, the lumbar spinal cord was postfixed following perfusion. Frontal frozen sections of 40nm were immunostained according to the peroxidase-antiperoxidase method. The allodynic threshold was checked with 8 calibrated von Frey filaments. MK-801 (0.3 mg/kg), morphine (3 mg/kg) and saline (as a placebo) were administered subcutaneously 30 min before, and 24 and 48 hrs after surgery. The tactile threshold decreased below 3 g since 2 days after surgery in the saline and morphine groups, but delayed a little in the MK-801 group. In the superficial layer the number of Fos-like immunoreactive neurones (Fos-LI) peaked at 2 hours and decreased thereafter, and reached normal levels 24 hrs following operation, for all groups. In the deep layer they were biphasic, - peaking at 2 and 24 hrs - in the saline group, but were suppressed in the morphine and MK-801 groups until 7 days following operation. The above discrepancy between the number of Fos-LI and the allodynic threshold showed that central sensitizations are not critically involved in the development of nerve injury induced tactile allodynia.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Spinal Cord
/
Spinal Nerves
/
Wounds and Injuries
/
Dizocilpine Maleate
/
Proto-Oncogene Proteins c-fos
/
Rats, Sprague-Dawley
/
Excitatory Amino Acid Antagonists
/
Hyperesthesia
/
Analgesics, Opioid
/
Ligation
Limits:
Animals
Language:
English
Journal:
Yonsei Medical Journal
Year:
2002
Type:
Article
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