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Delta opiate receptors mediate tail-shock induced antinociception at supraspinal levels
- Source :
- Brain Research. 582:10-21
- Publication Year :
- 1992
- Publisher :
- Elsevier BV, 1992.
-
Abstract
- Previous work has demonstrated that 3 pharmacologically and neuroanatomically distinct analgesia systems can be sequentially activated by increasing numbers of transcutaneous tail-shock. To date, the categorization of the early (after 2 tail-shocks) and late (after 80–100 tail-shocks) analgesias as opiate-mediated has been based on the ability of systemic naltrexone and morphine tolerance to block these effects. In contrast, the analgesia observed after 5–40 tail-shocks is unaffected by these manipulations, leading to its categorization as non-opiate. The preceding companion paper and the present work were aimed at identifying the neuroanatomical loci at which opiates exert their analgesic effects in this tail-shock paradigm and, further, to identify which opiate receptor subtypes are involved. The 8 experiments included in the present paper examined the effect of microinjecting either naltrexone (a relatively non-selective opiate receptor antagonist), binaltorphimine (kappa receptor antagonist), Cys2-Tyr3-Orn5-Pen7-amide (CTOP) (mu receptor antagonist), or naltrindole (delta receptor antagonist) either into the third ventricle or over the frontal cortex. Taken together, these experiments demonstrate that the late (80–100 shock) opiate analgesia is mediated by delta opiate receptors located within subcortical structures rostral to the 4th ventricle. No evidence for supraspinal opiate involvement in the early (2 shock) opiate analgesia was found.
- Subjects :
- Male
medicine.medical_specialty
Indoles
medicine.drug_class
Narcotic Antagonists
Pain
κ-opioid receptor
Cerebral Ventricles
δ-opioid receptor
Naltrindole
Receptors, Opioid, delta
Internal medicine
medicine
Animals
Molecular Biology
Injections, Spinal
Injections, Intraventricular
Analysis of Variance
Electroshock
Dose-Response Relationship, Drug
General Neuroscience
Rats, Inbred Strains
Receptor antagonist
Naltrexone
Rats
Binaltorphimine
Endocrinology
Morphinans
Spinal Cord
Opioid
Receptors, Opioid
Neurology (clinical)
μ-opioid receptor
Opiate
Psychology
Developmental Biology
medicine.drug
Subjects
Details
- ISSN :
- 00068993
- Volume :
- 582
- Database :
- OpenAIRE
- Journal :
- Brain Research
- Accession number :
- edsair.doi.dedup.....b6af69336899c31d40ee6d672cf87722