Fentanyl Induces Behavioral Sensitization and Decreases Class IIa HDAC Expression-Activity in Brain as Measured by...

Area of Science:

• Neuroscience
• Epigenetics
• Pharmacology

Background:

• Fentanyl contributes to opioid-related morbidity and mortality.
• Epigenetic changes may influence long-term neuronal adaptations to fentanyl.
• Understanding these changes is crucial for addressing opioid addiction.

Purpose of the Study:

• Investigate the effects of repeated fentanyl on class IIa histone deacetylase (HDAC) expression-activity.
• Utilize positron emission tomography (PET) imaging and a radiotracer ([18F]TFAHA).
• Examine fentanyl-induced behavioral sensitization in a rat model.

Main Methods:

• Administered fentanyl (20 μg/kg) or saline daily for 14 days to female and male Wistar rats.
• Measured locomotor activity (LMA) and performed PET imaging at baseline and after a challenge dose.
• Calculated percent change in standard uptake value (SUV) as a measure of class IIa HDAC expression-activity.

Main Results:

• Repeated fentanyl exposure significantly increased LMA in both sexes.
• Females exhibited an earlier onset and greater magnitude of behavioral sensitization compared to males.
• Fentanyl decreased class IIa HDAC expression-activity in the whole brain and reward regions, without sex differences.

Conclusions:

• Prolonged fentanyl exposure induces robust, sex-specific locomotor sensitization.
• Fentanyl appears to induce brain-wide epigenetic changes independent of sex.
• The impact of fentanyl on class II HDACs may not directly correlate with behavioral sensitization expression.