AI Article Synopsis
- The study investigated the impact of mGluR1 on pain responses in rats after formalin injection into their paws, utilizing antisense oligonucleotides to inhibit mGluR1 expression in the spinal cord.
- Rats receiving mGluR1 antisense treatment exhibited a significant reduction in the sustained pain phase after two days, but not in the immediate pain phase.
- The down-regulation of mGluR1 expression by 46% lasted for several days, indicating its potential critical role in managing prolonged pain responses.
Article Abstract
To examine the role of mGluR1 (a subunit of the group I metabotropic glutamate receptor) in the nociceptive responses of rats following a subcutaneous injection of formalin into the plantar surface of the hind paw, we delivered antisense oligonucleotides (ODNs) against mGluR1 into the rat lumbar spinal cord (L3-L5) intrathecally using an HVJ-liposome-mediated gene transfer method. Rats treated with a single injection of mGluR1 antisense ODNs into the intrathecal space of the lumbar spinal cord showed a marked reduction of the early-sustained phase of formalin-induced nociceptive responses, but not of their acute phase. The reduction of nociceptive behavioral responses became apparent at day 2 after the antisense treatment and lasted for 2 days. This corresponded to a long-lasting down-regulation (46%) of mGluR1 expression in the lumbar cord. This down-regulated mGluR1 was observed at day 2 and persisted until day 4 after the intrathecal infusion of mGluR1 antisense ODN. In contrast, rats treated with mGluR1 sense or mismatch ODNs showed none of these changes. These results suggest that mGluR1 may play a crucial role in the sustained nociception of formalin-induced behavioral responses.
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| http://dx.doi.org/10.1016/s0006-8993(03)03330-4 | DOI Listing |
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