Morphine Induced Hyperglycemia and Analgesic Tolerance assessment | Protocol Preview

Summary

This video outlines an experiment designed to observe opioid-induced hyperalgesia and analgesic tolerance in mice. The procedure involves daily measurements of thermal and mechanical nociceptive responses following morphine administration. Over seven days, the development of pain hypersensitivity and analgesic tolerance is tracked, revealing an increase in pain sensitivity after repeated morphine use. The method is adaptable for other opioids or genetically modified mice and includes measures to minimize stress-induced analgesia, such as daily habituation for tail immersion testing.

Takeaways

• 🧪 The experiment aims to study opioid-induced hyperalgesia and analgesic tolerance in mice.
• 🐭 Mice are used as test subjects to observe changes in pain sensitivity after morphine administration.
• ⏱️ On day zero, both thermal and mechanical nociceptive responses are measured to establish a baseline.
• 💉 Morphine is administered daily, and the nociceptive threshold is measured before each dose.
• 📆 On the seventh day, morphine’s analgesic effect is tested again to assess tolerance development.
• 🔥 Thermal sensitivity is measured using the tail immersion test at 48°C.
• 📉 Results show increased pain sensitivity and reduced analgesic effectiveness after repeated morphine use.
• 🔬 The procedure helps understand mechanisms of pain hypersensitivity and tolerance due to chronic opiate exposure.
• 🧬 The same experimental approach can be applied to other opioids or genetically modified mice.
• 🐾 Mice are habituated and handled daily for five minutes to minimize stress-induced analgesia before testing.

Q & A

What is the main objective of the experiment described in the transcript?

The main objective of the experiment is to observe the development of opioid-induced hyperalgesia and analgesic tolerance in mice.

How is the thermal and mechanical nociceptive response measured in naive mice?

The nociceptive response is measured by testing the thermal and mechanical sensitivity of naive mice after morphine administration over a specific time course.

What happens on day zero of the experiment?

On day zero, the nociceptive threshold of the mice is measured before morphine administration.

What does the experiment measure on the seventh day?

On the seventh day, the analgesic effect of morphine is measured over a time course to reveal the development of analgesic tolerance.

What were the results of the experiment?

The results showed an increase in pain sensitivity and the development of analgesic tolerance following repeated morphine administration.

Can this procedure be applied to other types of opioids or genetically modified mice?

Yes, the procedure can be applied to other opioids or genetically modified mice to study pain hypersensitivity and analgesic tolerance.

Who is involved in demonstrating the procedure?

The procedure is demonstrated by Safiyashi, a graduate student from the laboratory.

How does the experiment minimize stress-induced analgesia in the mice?

To minimize stress-induced analgesia, the mice are handled for five minutes every day and habituated until they freely enter the restrainer.

What is the purpose of the tail immersion test in this experiment?

The tail immersion test is used to measure the thermal nociceptive response of the mice by immersing the tail in water at 48°C.

How is the tail immersion test conducted?

The mouse is gently introduced into a restrainer, and two-thirds of its tail is dipped into a water bath set to 48°C. The chronometer is then started to measure the response time.