Intrathecal Lamotrigine Attenuates Antinociceptive Morphine Tolerance and Suppresses Spinal Glial Cell Activation in Morphine-Tolerant Rats.
10.3346/jkms.2013.28.2.300
- Author:
In Gu JUN
1
;
Sung Hoon KIM
;
Yang In YOON
;
Jong Yeon PARK
Author Information
1. Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. jongyeon_park@amc.seoul.kr
- Publication Type:Original Article
- Keywords:
Astrocyte;
Intrathecal;
Lamotrigine;
Microglia;
Morphine;
Tolerance
- MeSH:
Analgesics/*pharmacology;
Animals;
Antigens, CD11b/metabolism;
Astrocytes/cytology;
Drug Tolerance;
Immunohistochemistry;
Male;
Microglia/cytology;
Morphine/*pharmacology;
Nerve Tissue Proteins/metabolism;
Neuroglia/cytology/*metabolism;
Rats;
Rats, Sprague-Dawley;
Spinal Cord/*cytology;
Triazines/*pharmacology
- From:Journal of Korean Medical Science
2013;28(2):300-307
- CountryRepublic of Korea
- Language:English
-
Abstract:
Glial cells play a critical role in morphine tolerance, resulting from repeated administration of morphine. Both the development and the expression of tolerance are suppressed by the analgesic lamotrigine. This study investigated the relationship between the ability of lamotrigine to maintain the antinociceptive effect of morphine during tolerance development and glial cell activation in the spinal cord. In a rat model, morphine (15 microg) was intrathecally injected once daily for 7 days to induce morphine tolerance. Lamotrigine (200 microg) was co-administered with morphine either for 7 days or the first or last 3 days of this 7 day period. Thermal nociception was measured. OX-42 and GFAP immunoreactivity, indicating spinal microglial and astrocytic activation were evaluated on day 8. Tolerance developed after 7 days of intrathecal morphine administration; however, this was completely blocked and reversed by co-administration of lamotrigine. When lamotrigine was coinjected with morphine on days 5-7, the morphine effect was partially restored. Glial cell activation increased with the development of morphine tolerance but was clearly inhibited in the presence of lamotrigine. These results suggest that, in association with the suppression of spinal glial cell activity, intrathecally coadministered lamotrigine attenuates antinociceptive tolerance to morphine.
