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Mitragynine and morphine produce dose-dependent bimodal action on food but not water intake in rats.
Mitragynine and morphine produce dose-dependent bimodal action on food but not water intake in rats.
- Source :
-
American journal of physiology. Regulatory, integrative and comparative physiology [Am J Physiol Regul Integr Comp Physiol] 2024 Dec 01; Vol. 327 (6), pp. R568-R579. Date of Electronic Publication: 2024 Sep 09. - Publication Year :
- 2024
-
Abstract
- Kratom ( Mitragyna speciosa ), containing the primary alkaloid mitragynine, has emerged as an alternative self-treatment for opioid use disorder. Mitragynine binds numerous receptor types, including opioid receptors, which are known to modulate food consumption. However, the ability of acute mitragynine to modulate food consumption remains unknown. The current study assessed the effects of acute mitragynine or morphine administration on unconditioned food and water intake in 16 Sprague-Dawley rats. Food and water intake changes were monitored in response to morphine, mitragynine (1.78-56 mg/kg ip), saline, or vehicle controls for 12 h, starting at the onset of the dark cycle. Naltrexone pretreatment was used to examine pharmacological specificity. Both morphine and mitragynine demonstrated a biphasic food intake dose-effect, with low doses (5.6 mg/kg) increasing and high doses (56 mg/kg) decreasing food intake. All morphine doses reduced water intake; however, only the highest dose of mitragynine (56 mg/kg) reduced water intake. Naltrexone attenuated both stimulatory and inhibitory effects of morphine on food intake, but only the stimulatory effect of mitragynine. In conclusion, low doses of mitragynine stimulate food intake via opioid-related pathways, while high doses likely recruit other targets. NEW & NOTEWORTHY This study reveals that morphine and the kratom alkaloid mitragynine produce dose-dependent effects on feeding in rats. Low doses stimulate food intake via opioid pathways, while high doses decrease consumption through nonopioid mechanisms. Morphine potently suppresses water intake at all doses, whereas only high doses of mitragynine reduce drinking. These findings provide novel insights into the complex opioid and nonopioid mechanisms underlying the effects of mitragynine on ingestive behaviors.
- Subjects :
- Animals
Male
Rats
Drinking drug effects
Narcotic Antagonists pharmacology
Naltrexone pharmacology
Naltrexone administration & dosage
Analgesics, Opioid pharmacology
Analgesics, Opioid administration & dosage
Feeding Behavior drug effects
Secologanin Tryptamine Alkaloids pharmacology
Secologanin Tryptamine Alkaloids administration & dosage
Morphine pharmacology
Morphine administration & dosage
Rats, Sprague-Dawley
Dose-Response Relationship, Drug
Eating drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 1522-1490
- Volume :
- 327
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Regulatory, integrative and comparative physiology
- Publication Type :
- Academic Journal
- Accession number :
- 39250542
- Full Text :
- https://doi.org/10.1152/ajpregu.00128.2024