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Synergistic effects between intrathecal clonidine and neostigmine in the formalin test
- Source :
- Journal of Korean Medical Science
- Publication Year :
- 2001
- Publisher :
- Korean Academy of Medical Sciences, 2001.
-
Abstract
- Spinal alpha-2 adrenoceptors and cholinergic receptors are involved in the regulation of acute nociception and the facilitated processing. The aim of this study was to examine the pharmacological effect of an intrathecal alpha-2 agonist and a cholinesterase inhibitor on the facilitated pain model induced by formalin injection and to determine the nature of drug interaction using an isobolographic analysis. Both intrathecal clonidine and neostigmine dose-dependently suppressed the flinching during phase 1 and phase 2. Intrathecal pretreatment with atropine reversed the antinociceptive effects of clonidine and neostigmine in both phases. Pretreatment with intrathecal yohimbine attenuated the effect of clonidine. The antinociception of clonidine and neostigmine was not reversed by mecamylamine. Isobolographic analysis showed that intrathecal clonidine and neostigmine acted synergistically in both phase 1 and 2. Intrathecal pretreatment with atropine and yohimbine antagonized the effect of the mixture of clonidine and neostigmine in both phases, but no antagonism was observed with mecamylamine pretreatment. These data indicate that spinal clonidine and neostigmine are effective to counteract the facilitated state evoked formalin stimulus, and these two drugs interact in a synergistic fashion. In addition, the analgesic action of intrathecal clonidine is mediated by spinal muscarinic receptors as well as alpha-2 adrenoceptors.
- Subjects :
- Agonist
Male
medicine.drug_class
Analgesic
Pain
Pharmacology
Clonidine
Rats, Sprague-Dawley
Formaldehyde
Mecamylamine
medicine
Animals
Injections, Spinal
Dose-Response Relationship, Drug
business.industry
Drug Synergism
General Medicine
Analgesics, Non-Narcotic
Neostigmine
Yohimbine
Rats
Atropine
Nociception
Cholinesterase Inhibitors
business
Adrenergic alpha-Agonists
medicine.drug
Research Article
Subjects
Details
- Language :
- English
- ISSN :
- 15986357 and 10118934
- Volume :
- 16
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Journal of Korean Medical Science
- Accession number :
- edsair.doi.dedup.....2cb291882dd27d4fd5f23a0a0de8b926