Nociceptive behaviour upon modulation of mu-opioid receptors in the ventrobasal complex of the thalamus of rats

Autor: Fani Neto, Daniel Humberto Pozza, José Manuel Castro-Lopes, Patrícia Araújo Barroso, Catarina Soares Potes, Luís Filipe Azevedo
Přispěvatelé: Faculdade de Medicina
Rok vydání: 2010
Předmět:
Male
Pain Threshold
Agonist
Time Factors
Enkephalin
medicine.drug_class
Narcotic Antagonists
Receptors
Opioid
mu
Pain
Pharmacology
Ventrobasal complex
Ciências da Saúde
Outras ciências médicas
chemistry.chemical_compound
Opioid receptor
Reaction Time
medicine
Animals
Drug Interactions
Health sciences
Other medical sciences
Rats
Wistar
Opioid peptide
Pain Measurement
Inflammation
Analysis of Variance
Ventral Thalamic Nuclei
Behavior
Animal
business.industry
Chronic pain
Other medical sciences [Medical and Health sciences]
Enkephalin
Ala(2)-MePhe(4)-Gly(5)
medicine.disease
Rats
Analgesics
Opioid
Disease Models
Animal
DAMGO
Anesthesiology and Pain Medicine
Nociception
Neurology
chemistry
Anesthesia
Neurology (clinical)
Ankle
Somatostatin
Outras ciências médicas [Ciências médicas e da saúde]
business
Zdroj: Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP
ISSN: 0304-3959
DOI: 10.1016/j.pain.2009.12.013
Popis: The role of mu-opioid receptors (MORs) in the inflammatory pain processing mechanisms within the ventrobasal complex of the thalamus (VB) is not well understood. This study investigated the effect of modulating MOR activity upon nociception, by stereotaxically injecting specific ligands in the VB. Nociceptive behaviour was evaluated in two established animal models of inflammatory pain, by using the formalin (acute and tonic pain) and the ankle-bend (chronic monoarthritic pain) tests. Control (saline intra-VB injection) formalin-injected rats showed acute and tonic pain-related behaviours. In contrast, intrathalamic administration of [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin acetate (DAMGO), a MOR-specific agonist, induced a statistically significant decrease of all tonic phase pain-related behaviours assessed until 30–35 min after formalin hind paw injection. In the acute phase only the number of paw-jerks was affected. In monoarthritic rats, there was a noticeable antinociceptive effect with approximately 40 min of duration, as denoted by the reduced ankle-bend scores observed after DAMGO injection. Intra-VB injection of D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), a specific MOR antagonist, or of CTOP followed, 10 min after, by DAMGO had no effects in either formalin or ankle-bend tests. Data show that DAMGO-induced MOR activation in the VB has an antinociceptive effect in the formalin test as well as in chronic pain observed in MA rats, suggesting an important and specific role for MORs in the VB processing of inflammatory pain.
Databáze: OpenAIRE
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