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Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Agmatine blocks morphine-evoked hyperthermia in rats
Scott M Rawls1, Manisha Amin, Jacob Zisk
1Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, PA 19140, USA. scott.rawls@temple.edu
Brain Research
|March 23, 2007
Summary
Agmatine reduces morphine-induced hyperthermia in rats by activating imidazoline receptors. This effect was blocked by idazoxan, suggesting a specific mechanism for agmatine in modulating opioid-induced temperature changes.
Area of Science:
- Pharmacology
- Neuroscience
- Pain Research
Background:
- Morphine, a potent analgesic, can induce hyperthermia through mu opioid receptor activation.
- Agmatine, an endogenous neuromodulator, has shown diverse effects on various physiological systems.
- The interaction between agmatine and opioid-induced hyperthermia is not well understood.
Purpose of the Study:
- To investigate the effect of agmatine on morphine-evoked hyperthermia in a rat model.
- To elucidate the receptor mechanisms involved in agmatine's potential modulation of morphine-induced hyperthermia.
Main Methods:
- Rats were administered morphine (4 mg/kg, s.c.) to induce hyperthermia.
- Agmatine (10 and 50 mg/kg, i.p.) was administered alone and in combination with morphine.
- The effects of co-administration with idazoxan (imidazoline/alpha(2)-adrenoeceptor antagonist) and yohimbine (alpha(2)-adrenoeceptor antagonist) were examined.
Main Results:
- Agmatine alone did not affect body temperature.
- Co-administration of agmatine significantly decreased morphine-evoked hyperthermia.
- The hyperthermic effect of morphine was attenuated by agmatine, and this effect was blocked by idazoxan.
- Yohimbine did not prevent the attenuation of morphine-induced hyperthermia by agmatine.
Conclusions:
- Agmatine attenuates morphine-induced hyperthermia in rats.
- The findings suggest that agmatine exerts its effect by activating imidazoline receptors.
- Agmatine represents a potential therapeutic target for managing opioid-induced side effects.
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