To determine the role of mu-opioid receptor subtypes, mu1 and mu2, in antinociception induced by intrathecal (i.t.) or intracerebroventricular (i.c.v.) injection of morphine, we assessed the effect of naloxonazine, a selective antagonist at mu1-opioid receptors. The antinociceptive effects of morphine were measured using four different nociceptive tests. The selective mu1 antagonist, naloxonazine (35 mg/kg, s.c.), 24 h before testing antagonized the antinociceptive effect of morphine on responses to chemical and thermal stimuli to a greater extent than that on responses to mechanical stimuli, as judged from ED50 values. The present results suggest that the antinociceptive activity of both i.t. and i.c.v. morphine on responses to chemical and thermal stimuli may be mediated through the mu1-opioid receptor subtype (naloxonazine-sensitive sites). These findings may be interpreted as indicative of the existence of mu1-receptor subtypes capable of mediating antinociception not only in supraspinal sites but also in spinal sites.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/s0014-2999(99)00065-5 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A 9-aminoacridine derivative induces growth inhibition of Ehrlich ascites carcinoma cells and antinociceptive effect in mice.
Front Pharmacol
October 2022
Post Graduation Program in Bioactive Natural and Synthetic Products, Federal University of Paraíba, João Pessoa, Brazil.
Acridine derivatives have been found with anticancer and antinociceptive activities. Herein, we aimed to evaluate the toxicological, antitumor, and antinociceptive actions of N'-(6-chloro-2-methoxyacridin-9-yl)-2-cyanoacetohydrazide (ACS-AZ), a 9-aminoacridine derivative with antimalarial activity. The toxicity was assessed by acute toxicity and micronucleus tests in mice.
View Article and Find Full Text PDFThe blockade of μ‑opioid receptors in the lateral hypothalamus enhances panic attack‑like behaviour and diminishes defensive antinociception.
Acta Neurobiol Exp (Wars)
July 2022
Laboratory of Experimental Neuropsychobiology and Toxicology, Institute of Health Sciences, Mato Grosso Federal University (UFMT), Mato Grosso, Brazil;
The lateral hypothalamus (LH) sends neural pathways to structures involved on predator‑related defensive behaviours, escape and antinociception. The aim of this study was to investigate the role played by μ-opioid receptors located on LH neurons in defensive behaviour and unconditioned fear‑induced antinociception elicited by electric stimulation of LH. To achieve the goals, the μ1-opioid receptor selective antagonist naloxonazine was administered at different concentrations in the LH, and the defensive behaviour and fear‑induced antinociception elicited by electrical stimulation of LH were evaluated.
View Article and Find Full Text PDFPolymorphism of Opioid Receptors μ1 in Highly Hypnotizable Subjects.
Int J Clin Exp Hypn
February 2019
a University of Pisa, Italy.
The possible cooperation between hypnotizability-related and placebo mechanisms in pain modulation has not been consistently assessed. Here, we investigate possible genetic bases for such cooperation. The OPRM1 gene, which encodes the μ1 opioid receptor-the primary site of action for endogenous and exogenous opioids-is polymorphic in the general population for the missense mutation Asn40Asp (A118G, rs1799971).
View Article and Find Full Text PDFEvidence for the involvement of opioid system in the antidepressant-like effect of ascorbic acid.
Naunyn Schmiedebergs Arch Pharmacol
February 2018
Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
Considering the involvement of the opioid system in major depressive disorder (MDD), mainly concerning refractory MDD, and the evidence that ascorbic acid may exert a beneficial effect for the treatment of this disorder, this study investigated the involvement of the opioid system in the antidepressant-like effect of ascorbic acid in the tail suspension test (TST). Treatment of Swiss mice with the non-selective opioid receptor antagonist naloxone (1 mg/kg, i.p.
View Article and Find Full Text PDFIndividual variability in clinical effect and tolerability of opioid analgesics - Importance of drug interactions and pharmacogenetics.
Scand J Pain
October 2017
Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Norway. Electronic address:
Background: As pain is often a comorbid condition, many patients use opioid analgesics in combination with several other drugs. This implies a generally increased risk of drug interactions, which along with inherent pharmacogenetic variability and other factors may cause differences in therapeutic response of opioids.
Aim: To provide an overview of interactions and pharmacogenetic variability of relevance for individual differences in effect and tolerability of opioid analgesics, which physicians and other healthcare professionals should be aware of in clinical practice.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!