Ghrelin Receptor Agonist Hexarelin Reduces Morphine Tolerance and Enhances Pain Relief in Rats
Hexarelin (GHS-R agonist) combined with morphine attenuated analgesic tolerance development and enhanced pain relief in rats, while the GHS-R antagonist had no significant effect.
Quick Facts
What This Study Found
Hexarelin (0.2 mg/kg) combined with morphine attenuated analgesic tolerance and enhanced antinociception in tail-flick and hot-plate tests. The GHS-R antagonist [d-Lys3]-GHRP-6 showed no significant effect on morphine tolerance.
Key Numbers
104 rats; hexarelin attenuated morphine tolerance; [D-Lys3]-GHRP-6 had no effect; tested by tail-flick and hot plate.
How They Did This
104 Wistar rats. Three-day cumulative morphine dosing regimen to induce tolerance. Day 4 assessment of tolerance with hexarelin, GHS-R antagonist, and morphine combinations. Tail-flick and hot-plate analgesic tests at 30-min intervals.
Why This Research Matters
Morphine tolerance forces dose escalation, increasing side effects and addiction risk. A peptide that can maintain morphine's effectiveness at lower doses could improve pain management while reducing opioid-related harms.
The Bigger Picture
The opioid crisis demands strategies to maintain analgesic efficacy while minimizing dose escalation. Ghrelin receptor activation represents a novel mechanism for achieving this, distinct from the traditional opioid receptor pathways targeted by most current approaches.
What This Study Doesn't Tell Us
Acute tolerance model in rats — may not fully replicate chronic tolerance in human patients. Mechanism by which hexarelin attenuates tolerance not fully elucidated. Clinical applicability and dosing for humans unknown.
Questions This Raises
- ?Could hexarelin or similar GHS-R agonists be co-administered with opioids clinically to reduce tolerance?
- ?What is the mechanism by which ghrelin receptor activation modulates opioid tolerance?
- ?Would this approach also reduce other opioid side effects like respiratory depression?
Trust & Context
- Key Stat:
- Attenuated tolerance hexarelin combined with morphine slowed analgesic tolerance development in multiple pain tests
- Evidence Grade:
- Well-designed preclinical study with appropriate sample size (104 rats) and multiple analgesic outcome measures. Clinical translation needs further investigation.
- Study Age:
- Published in 2021. Ghrelin system modulation of opioid responses remains an active research area.
- Original Title:
- Ghrelin receptor agonist hexarelin attenuates antinociceptive tolerance to morphine in rats.
- Published In:
- Canadian journal of physiology and pharmacology, 99(5), 461-467 (2021)
- Database ID:
- RPEP-05272
Evidence Hierarchy
Frequently Asked Questions
What is morphine tolerance?
After repeated use, the body adapts to morphine so that the same dose provides less pain relief. This forces doctors to increase doses, which raises the risk of side effects, dependence, and overdose.
How could a ghrelin receptor agonist help with pain?
Ghrelin receptor activation appears to modulate how the brain responds to opioids, helping maintain their pain-relieving effects over time. This could allow lower opioid doses to remain effective, reducing side effects and addiction risk.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-05272APA
Baser, Tayfun; Ozdemir, Ercan; Filiz, Ahmet Kemal; Taskiran, Ahmet Sevki; Gursoy, Sinan. (2021). Ghrelin receptor agonist hexarelin attenuates antinociceptive tolerance to morphine in rats.. Canadian journal of physiology and pharmacology, 99(5), 461-467. https://doi.org/10.1139/cjpp-2020-0218
MLA
Baser, Tayfun, et al. "Ghrelin receptor agonist hexarelin attenuates antinociceptive tolerance to morphine in rats.." Canadian journal of physiology and pharmacology, 2021. https://doi.org/10.1139/cjpp-2020-0218
RethinkPeptides
RethinkPeptides Research Database. "Ghrelin receptor agonist hexarelin attenuates antinociceptiv..." RPEP-05272. Retrieved from https://rethinkpeptides.com/research/baser-2021-ghrelin-receptor-agonist-hexarelin
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.