Exploring Exercise- and Context-Induced Peptide Changes in Mice by Quantitative Mass Spectrometry.

Area of Science:

• Neuroscience
• Addiction Research
• Exercise Physiology

Background:

• Exercise shows promise in aiding cocaine abstinence, but underlying brain mechanisms remain unclear.
• Wheel running in mice models cocaine addiction extinction, aiding study of neurological underpinnings.
• Endogenous peptide changes in response to cocaine cues and exercise are not well characterized.

Purpose of the Study:

• To quantify dynamic changes in endogenous peptides within the amygdala and hippocampus.
• To investigate these peptide changes in mice exposed to cocaine-associated contexts and exercise.
• To identify potential peptide biomarkers associated with exercise and cocaine addiction.

Main Methods:

• Male C57BL/6J mice underwent cocaine conditioning and were housed with or without running wheels.
• Conditioned place preference (CPP) tests were conducted, followed by brain tissue extraction.
• Label-free MALDI-MS and LC-ESI-MS with stable isotopic labeling were used to measure peptides.

Main Results:

• Wheel running significantly reduced CPP for cocaine in mice.
• Reduced myelin basic protein derivatives in the dentate gyrus correlated with decreased CPP.
• Exercise altered hemoglobin- and actin-derived peptides in response to cocaine-paired contexts.

Conclusions:

• Exercise, particularly wheel running, effectively reduces cocaine-associated behaviors in mice.
• Specific peptide changes in the hippocampus and amygdala are associated with exercise and cocaine cue exposure.
• These findings identify novel peptide biomarkers for exercise responsiveness in addiction models.