Effect of ketamine on iNOS mRNA expression in spinal cord of mice in the development of morphine tolerance
- VernacularTitle:吗啡耐受形成过程中氯胺酮对小鼠脊髓诱导型一氧化氮合酶mRNA表达的影响
- Author:
Hongbing XIANG
;
Yuke TIAN
;
Yi SUN
- Publication Type:Journal Article
- Keywords:
Morphine dependence;
Ketamine;
Nitric-oxide synthase;
RNA,messenger;
Spinal cord
- From:
Chinese Journal of Anesthesiology
1994;0(04):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effect of ketamine, the NMDA receptor antagonist, on inducible nitric oxide gynthase (iNOS) mRNA expression in the spinal cord during the development of morphine tolerance. Methods Thirty Kunming mice weighing 18-22 g were randomly divided into 5 groups ( n = 6 each): A control group received normal saline (NS) only; B chronic morphine tolerance group received subcutaneous morphine 10 mg?kg-1 followed by IP NS after an interval of 30 min, twice a day for 9 days and C, D, E ketamine groups received subcutaneous morphine 10 mg?kg-1 followed by IP ketamine 5 (group C) or 10 (group D) or 20 (group E) mg?kg-1 after an interval of 30 min, twice a day for 9 days. One hour after the last drug administration the animals were decapitated and the lumbar enlargement of the spinal cord was isolated and the iNOS mRNA expression in the spinal cord was detected by RT-PCR. Results Expression of iNOS mRNA was not detectable in group A but increased dramatically in group B. The iNOS mRNA expression was significantly lower in group D and E (ketamine 10 and 20 mg?kg-1 IP) than in group B and C (ketamine 5 mg?kg-1) . Conclusion Ketamine antagonizes the development of chronic morphine tolerance in mice through down-regulation of iNOS mRNA expression in the spinal cord.
