Dopamine receptor stimulation does not modulate the loudness dependence of the auditory evoked potential in humans

Rationale The Loudness Dependence of the Auditory Evoked Potential (LDAEP) has been suggested as a reliable measure of central serotonin function in humans; however, its specificity for the serotonin system remains a topic of debate, with possible modulation of this purported serotonin marker by other neurotransmitters, including dopamine.Objectives We examined the effect of dopaminergic modulation on the LDAEP using the D₁/D₂/D₃ dopamine receptor agonist pergolide and the D₂/D₃ agonist bromocriptine.Methods The study was a double-blind, placebo-controlled repeated-measures design in which healthy participants were tested under three acute treatment conditions: placebo, bromocriptine (2.5 mg), and pergolide (0.1 mg). Changes in the amplitude of the N1/P2 at intensities (60, 70, 80, 90, and 100 dB) were examined at C _Z.Results Acute stimulation of D₁/D₂/D₃ receptors with pergolide and D₂/D₃ receptors with bromocriptine in comparison with placebo had no effect on the LDAEP.Conclusion These findings indicate that acute stimulation of dopamine D₁, D₂, and D₃ receptors does not modulate the LDAEP in humans. Although the findings suggest that the LDAEP may not be modulated by acute changes in dopamine neurotransmission, further studies are needed to fully characterize its dopaminergic sensitivity.