Targeting GPR3 as a novel approach for nicotine cessation therapeutic development

Area of Science:

• Neuroscience
• Pharmacology
• Addiction Research

Background:

• Tobacco use is a leading cause of preventable death globally.
• Current nicotine cessation aids exhibit limited long-term effectiveness.
• G protein-coupled receptor 3 (GPR3) is expressed in brain regions crucial for nicotine dependence.

Purpose of the Study:

• To investigate GPR3 as a therapeutic target for nicotine cessation.
• To evaluate the efficacy of a novel GPR3 agonist, RTI-19318-32, in reducing nicotine self-administration in mice.

Main Methods:

• Administered RTI-19318-32 at varying doses to mice self-administering nicotine intravenously.
• Assessed the impact of RTI-19318-32 on nicotine intake, food reinforcement, anxiety, and locomotion.
• Utilized GPR3 knockout mice to confirm receptor specificity.
• Examined GPR3 co-localization with nicotinic acetylcholine receptor (nAChR) subunits in the medial habenula.

Main Results:

• RTI-19318-32 significantly reduced nicotine intake across all tested doses in both male and female mice.
• The compound demonstrated selectivity for GPR3, with no effect on nicotine intake in GPR3 knockout mice.
• Higher doses of RTI-19318-32 affected food reinforcement but not baseline food consumption, while lower doses showed selectivity for nicotine intake.
• GPR3 expression was found to co-localize with nAChR subunits in the medial habenula.

Conclusions:

• Activation of the GPR3 receptor by agonists like RTI-19318-32 is functionally significant for reducing nicotine consumption.
• GPR3 represents a promising therapeutic target for developing novel medications for nicotine cessation.
• Targeting GPR3 engagement with specific circuits may modulate the drive for nicotine consumption.