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Interaction between vanilloid and glutamate receptors in the central modulation of nociception
Interaction between vanilloid and glutamate receptors in the central modulation of nociception
- Publication Year :
- 2002
-
Abstract
- This study investigates the effect of microinjections of capsaicin in the periaqueductal grey matter of rats on nociceptive behaviour and the possible interactions with NMDA and mGlu receptors. Intra-periaqueductal grey microinjection of capsaicin (1-3-6 nmol/rat) increased the latency of the nociceptive reaction in the plantar test. This effect was prevented by pretreatment with capsazepine (6 nmol/rat), which had no effect per se on the latency of the nociceptive reaction. 7-(Hydroxyimino)cyclopropa[b]chromen-1alpha-carboxylate ethyl ester (CPCCOEt, 50 nmol/rat) and 2-Methyl-6-(phenylethynyl)pyridine (MPEP, 50 nmol/rat), antagonists of mGlu(1) and mGlu(5) receptors, respectively, completely blocked the effect of capsaicin. Similarly, pretreatment with DL-2-Amino-5-phosphonovaleric acid (DL-AP5, 5 nmol/rat) and riluzole (4 nmol/rat), an NMDA receptor antagonist and a voltage-dependent Na(+) channels blocker which inhibits glutamate release, respectively, completely antagonized the effect of capsaicin. However, pretreatment with (2S)-alpha-Ethylglutamic acid (30 nmol/rat) and (RS)-alpha-Methylserine-O-phosphate (MSOP, 30 nmol/rat), antagonists of group II and group III mGlu receptors, respectively, had no effects on capsaicin-induced analgesia. Similarly, pretreatment with N-(piperidin-1-yl)-5-(4-chlophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR 141716A, 5 pmol/rat), a selective cannabinoid CB(1) receptor antagonist, did not affect the capsaicin-induced antinociception. In conclusion, this study shows that capsaicin might produce antinociception at the periaqueductal grey level by increasing glutamate release, which activates postsynaptic group I mGlu and NMDA receptors.
- Subjects :
- Male
medicine.medical_specialty
Time Factors
medicine.drug_class
Pyridines
medicine.medical_treatment
Receptors, Drug
Pain
chemistry.chemical_compound
Phosphoserine
Piperidines
Internal medicine
medicine
Animals
Periaqueductal Gray
Rats, Wistar
2-Amino-5-phosphonovalerate
Pharmacology
Riluzole
Chemistry
Glutamate receptor
Receptor antagonist
Rats
Endocrinology
Receptors, Glutamate
Capsaicin
Chromones
NMDA receptor
Pyrazoles
Cannabinoid
Rimonabant
Capsazepine
Excitatory Amino Acid Antagonists
medicine.drug
Protein Binding
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....ebfc202befe76820e70fe817c19bcbb8