Algogenic mediator-induced nociceptive response in diabetic mice

Area of Science:

• Neuroscience
• Pharmacology
• Diabetology

Background:

• Diabetes mellitus is associated with altered pain perception.
• Opioid receptors play a crucial role in pain modulation.
• Bradykinin is a known mediator of nociception.

Purpose of the Study:

• To investigate the role of delta1-opioid receptors in the altered nociceptive responses observed in diabetic mice.
• To examine the effect of 7-benzylidenenaltrexone, a delta1-opioid receptor antagonist, on somatostatin-, bradykinin-, and prostaglandin F2alpha-induced pain in diabetic and non-diabetic mice.

Main Methods:

• Utilized a mouse model of diabetes.
• Administered somatostatin, bradykinin, or prostaglandin F2alpha to induce nociceptive responses.
• Administered 7-benzylidenenaltrexone (a delta1-opioid receptor antagonist) subcutaneously at various doses.
• Assessed the duration of nociceptive responses.

Main Results:

• Diabetic mice exhibited significantly shorter durations of somatostatin-, bradykinin-, and prostaglandin F2alpha-induced nociceptive responses compared to non-diabetic mice.
• 7-Benzylidenenaltrexone had no significant effect on nociceptive responses in non-diabetic mice.
• In diabetic mice, 7-benzylidenenaltrexone did not affect somatostatin- or prostaglandin F2alpha-induced responses but significantly and dose-dependently increased bradykinin-induced nociception.

Conclusions:

• A spinal delta1-opioid receptor-mediated endogenous antinociceptive system appears to inhibit bradykinin-mediated nociception in diabetic mice.
• This system may be involved in modulating the second phase of formalin-induced nociceptive responses in diabetic conditions.