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CB 1 receptor antagonist SR141716A increases capsaicin‐evoked release of Substance P from the adult mouse spinal cord
Cannabinoids have an antinociceptive action in many pain models. We have investigated a possible modulatory role for Type 1 Cannabinoid receptors (CB 1 ) on the release of excitatory transmitter Substance P from the adult mouse spinal cord after stimulation of nociceptor terminals by capsaicin. Caps...
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Published in: | British journal of pharmacology 2009-01, Vol.135 (1), p.21-24 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Cannabinoids have an antinociceptive action in many pain models. We have investigated a possible modulatory role for Type 1 Cannabinoid receptors (CB
1
) on the release of excitatory transmitter Substance P from the adult mouse spinal cord after stimulation of nociceptor terminals by capsaicin. Capsaicin (0.1 – 10 μ
M
) was applied to superfused cord sections and evoked a dose dependent release of SP above basal outflow of (23.36±2.96 fmol 8 ml
−1
). Maximum evoked SP release was obtained with 5 μ
M
Capsaicin (262.4±20.8 fmol 8 ml
−1
). Higher capsaicin concentrations (50 – 100 μ
M
) evoked less SP release. Superfusion of CB
1
antagonist SR141716A (5 μ
M
) increased evoked SP release with capsaicin (0.1 – 10 μ
M
) and reversed the reducing effect of high dose capsaicin (100 μ
M
). Antagonism of CB
1
receptors in the spinal cord during capsaicin stimulation, is evidence of tonic CB
1
activity inhibiting the release of excitatory transmitters after activation of nociceptive neurones and is also indicative of endocannabinoid production during noxious stimulation.
British Journal of Pharmacology
(2002)
135
, 21–24; doi:
10.1038/sj.bjp.0704506 |
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ISSN: | 0007-1188 1476-5381 |
DOI: | 10.1038/sj.bjp.0704506 |