Dopamine D2 Receptor Modulates Exercise Related Effect on Cortical Excitation/Inhibition and Motor Skill Acquisition

• Published in: The Journal of neuroscience 2024-05, Vol.44 (19), p.e2028232024
• Main Authors: Curtin, Dylan, Taylor, Eleanor M, Bellgrove, Mark A, Chong, Trevor T-J, Coxon, James P
• Format: Article
• Language: English
• Subjects: Adult; Dopamine; Dopamine Antagonists - pharmacology; Dopamine D2 receptors; Double-Blind Method; Engines; Evoked Potentials, Motor - drug effects; Evoked Potentials, Motor - physiology; Excitation; Exercise - physiology; Female; Genotyping; Humans; Isometric; Learning; Learning - physiology; Magnetic fields; Male; Motor Cortex - drug effects; Motor Cortex - physiology; Motor skill; Motor skill learning; Motor Skills - drug effects; Motor Skills - physiology; Movement disorders; Neural Inhibition - drug effects; Neural Inhibition - physiology; Neurodegenerative diseases; Neurological diseases; Parkinson's disease; Placebos; Receptors; Receptors, Dopamine D2 - metabolism; Sensorimotor integration; Sulpiride; Sulpiride - pharmacology; Transcranial magnetic stimulation; Transcranial Magnetic Stimulation - methods; Visual pathways; Visual tasks; Young Adult
• ISSN: 0270-6474; 1529-2401; 1529-2401
• DOI: 10.1523/JNEUROSCI.2028-23.2024

Exercise is known to benefit motor skill learning in health and neurological disease. Evidence from brain stimulation, genotyping, and Parkinson's disease studies converge to suggest that the dopamine D2 receptor, and shifts in the cortical excitation and inhibition (E:I) balance, are prime candidates for the drivers of exercise-enhanced motor learning. However, causal evidence using experimental pharmacological challenge is lacking. We hypothesized that the modulatory effect of the dopamine D2 receptor on exercise-induced changes in the E:I balance would determine the magnitude of motor skill acquisition. To test this, we measured exercise-induced changes in excitation and inhibition using paired-pulse transcranial magnetic stimulation (TMS) in 22 healthy female and male humans, and then had participants learn a novel motor skill-the sequential visual isometric pinch task (SVIPT). We examined the effect of D2 receptor blockade (800 mg sulpiride) on these measures within a randomized, double-blind, placebo-controlled design. Our key result was that motor skill acquisition was driven by an interaction between the D2 receptor and E:I balance. Specifically, poorer skill learning was related to an attenuated shift in the E:I balance in the sulpiride condition, whereas this interaction was not evident in placebo. Our results demonstrate that exercise-primed motor skill acquisition is causally influenced by D2 receptor activity on motor cortical circuits.