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Formalin-induced nociceptive responses in diabetic mice
J Kamei1, H Hitosugi, Y Kasuya
1Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Neuroscience Letters
|January 12, 1993
Summary
Diabetic mice exhibit altered pain responses, with a prolonged immediate nociceptive response and a suppressed second phase. Delta-opioid receptor antagonists restored the second-phase pain response, suggesting a novel inhibitory pathway.
Area of Science:
- Neuroscience
- Pain Research
- Diabetic Complications
Background:
- Formalin injection in mice typically elicits biphasic nociceptive responses.
- Diabetic neuropathy can significantly alter pain perception and signaling pathways.
Purpose of the Study:
- To investigate the impact of diabetes on formalin-induced nociception in mice.
- To explore the role of substance P and delta-opioid receptors in diabetic pain modulation.
Main Methods:
- Subcutaneous formalin injection into the hindpaw of diabetic and non-diabetic mice.
- Administration of spantide (substance P antagonist) and naltrindole (delta-opioid receptor antagonist).
- Observation and measurement of nociceptive response phases and durations.
Main Results:
- Diabetic mice showed a prolonged first-phase nociceptive response and a diminished second-phase response compared to non-diabetic controls.
- Spantide administration restored the second-phase response in diabetic mice.
- Naltrindole pretreatment also revealed the second-phase response in diabetic mice.
Conclusions:
- Diabetes mellitus alters nociceptive processing, specifically inhibiting the second phase of the formalin test.
- A negative control system involving delta-opioid receptors and substance P may suppress the second-phase nociceptive response in diabetic mice.
- Targeting this delta-opioid mediated pathway could offer new therapeutic strategies for diabetic pain.