Interactions of "ultra-low" doses of naltrexone and morphine in mature and young male and female rats.

Recept Channels

Department of Anesthesiology, College of Medicine, University of Kentucky, Lexington, KY 40536-0293, USA.

Published: January 2005

Sex and age influence morphine analgesia in humans and animals. Mature rats show greater morphine analgesia in males than in females. Ultra-low doses of naltrexone enhance morphine analgesia. In mature rats (18-22 weeks), naltrexone (0.002-2.0 mg/kg)-morphine (2 mg/kg) cotreatment enhanced morphine analgesia in females, an effect inversely related to naltrexone dose. Conversely, in mature male rats, naltrexone tended to decrease morphine analgesia with increasing dose. In young rats (8-10 weeks), morphine analgesia was unrelated to sex and in both sexes the naltrexone-morphine interaction was negligible. These data show that dose, age, and sex alter the naltrexone-morphine interaction in rats.

Download full-text PDF

Source
http://dx.doi.org/10.1080/10606820490464334DOI Listing

Publication Analysis

Top Keywords

morphine analgesia
24
doses naltrexone
8
mature rats
8
naltrexone-morphine interaction
8
morphine
7
rats
6
analgesia
6
naltrexone
5
interactions "ultra-low"
4
"ultra-low" doses
4

Similar Publications

Breast cancer surgeries offer challenges in perioperative pain management, especially in the presence of inherent risk of postoperative nausea and vomiting (PONV) and postmastectomy pain syndrome (PMPS). Inappropriate opioid consumption was speculated as one of the reasons. Through this study, the influence of objective pain monitoring through a nociception level monitor (NOL) on perioperative course in breast surgeries was investigated.

View Article and Find Full Text PDF

The mu-opioid receptor (MOR) is a major target for the treatment of pain. However, opioids are prone to side effects which limit their effectiveness as analgesics and can lead to opioid use disorders or, even, lethal overdose. The systemic administration of opioid agonists makes it both very difficult to decipher their underlying circuit mechanisms of action and to limit drug action to specific receptor subpopulations to isolate therapeutic effects from adverse side effects.

View Article and Find Full Text PDF

Peripheral inflammation enhances opioid-induced gastrointestinal motility inhibition via up-regulating spinal mu opioid receptor.

Toxicol Appl Pharmacol

January 2025

Department of Animal and Biomedical Sciences, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China; Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China. Electronic address:

Opioids are potent analgesics in clinical pain management but exert variable analgesia in different pain types. Opioid-induced constipation is a common side effect of opioid therapy, and whether opioids induce different gastrointestinal motility inhibitions in different pain types is unknown. In this study, we evaluated the antinociceptive effects and inhibition of upper gastrointestinal transit and colonic bead expulsion of morphine, DAMGO, and Deltorphin in mouse CFA chronic inflammatory pain, SNI chronic neuropathic pain, and carrageenan chronic inflammatory pain models.

View Article and Find Full Text PDF

Pain Management in Brugada Syndrome: A Case Report and Review.

A A Pract

January 2025

Division of Anaesthesiology and Perioperative Medicine, Department of Pain Medicine, Singapore General Hospital, Singapore.

Article Synopsis
  • Brugada syndrome is a rare condition that elevates the risk of serious heart arrhythmias, with limited guidance on pain management for these patients.
  • A case study of a young woman with the syndrome highlights the use of ropivacaine peripheral nerve infusion and intravenous ketamine for managing her acute-on-chronic pain in the left upper limb.
  • The approach included a multimodal analgesia strategy with neuropathic agents and opioids, aiming to improve safe pain management practices for those with Brugada syndrome.
View Article and Find Full Text PDF

Background And Aims: Even though patient tolerance is critical to the success of noninvasive ventilation (NIV), research on using sedation to improve tolerance to NIV after traumatic chest injuries is limited. We hypothesized that dexmedetomidine would be superior to ketamine in terms of patient tolerance and lengthening the NIV sessions after blunt chest trauma.

Material And Methods: This randomized, double-blinded, placebo-controlled trial included 45 patients of both genders aged 18-60 who needed NIV after blunt chest trauma.

View Article and Find Full Text PDF

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!