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Pain relief caused by millimeter waves in mice: results of cold water tail flick tests
M A Rojavin1, A A Radzievsky, A Cowan
1Richard J Fox Center for Biomedical Physics, Philadelphia, PA 19140, USA.
Purpose:
To find out if millimeter waves can decrease experimental pain response in mice using cold water tail flick test.
Materials And Methods:
Male Swiss albino mice (15 mice per group) were exposed to continuous millimeter waves at a frequency of 61.22 GHz with incident power densities (IPD) ranging from 0.15 to 5.0 mW/cm2 for 15 min or sham exposed. Latency of tail withdrawal in a cold water (1 +/- 0.5 degrees C) tail flick test was measured before the exposure (baseline) and then four times after the exposure with 15 min breaks.
Results:
The mean latency of the tail flick response in mice exposed to millimeter waves was more than twice that of sham-exposed controls (p<0.05). This effect was proportional to the power of millimeter waves and completely disappeared at an IPD level of < or = 0.5 mW/cm2. Pretreatment of mice with the opioid antagonist naloxone (1 mg/kg i.p.) blocked the effect of millimeter waves.
Conclusions:
Results suggest that the antinociceptive effect of millimeter waves is mediated through endogenous opioids.
Insights
Millimeter waves significantly reduced pain responses in mice, acting similarly to opioids. This pain relief effect was dependent on the intensity of the millimeter wave exposure.
Area of Science:
- Biophysics
- Neuroscience
- Pain Research
Background:
- Experimental pain models are crucial for understanding nociception.
- Opioid pathways play a significant role in pain modulation.
Purpose of the Study:
- To investigate the potential of millimeter waves (MW) in mitigating experimental pain.
- To determine the efficacy of MW in reducing pain response using the cold water tail flick test in mice.
Main Methods:
- Male Swiss albino mice were exposed to 61.22 GHz millimeter waves at varying incident power densities (IPD) or sham exposed.
- Pain response was assessed using the cold water tail flick test, measuring tail withdrawal latency before and after exposure.
- The role of opioid pathways was examined by pretreating mice with naloxone, an opioid antagonist.
Main Results:
- Millimeter wave exposure more than doubled the tail flick latency compared to sham controls (p<0.05).
- The antinociceptive effect was power-dependent, diminishing at IPD levels of 0.5 mW/cm2 or lower.
- Naloxone pretreatment abolished the pain-reducing effect of millimeter waves.
Conclusions:
- Millimeter waves demonstrate a significant antinociceptive effect in a mouse model.
- The findings suggest that the pain relief induced by millimeter waves is mediated by the endogenous opioid system.
