Effects of selective and combined serotonin and dopamine depletion on the loudness dependence of the auditory evoked potential (LDAEP) in humans
Article first published online: 23 JAN 2008
Copyright © 2008 John Wiley & Sons, Ltd.
Human Psychopharmacology: Clinical and Experimental
Volume 23, Issue 4, pages 301–312, June 2008
How to Cite
O'Neill, B. V., Guille, V., Croft, R. J., Leung, S., Scholes, K. E., Phan, K. L. and Nathan, P. J. (2008), Effects of selective and combined serotonin and dopamine depletion on the loudness dependence of the auditory evoked potential (LDAEP) in humans. Hum. Psychopharmacol. Clin. Exp., 23: 301–312. doi: 10.1002/hup.926
- Issue published online: 22 MAY 2008
- Article first published online: 23 JAN 2008
- Manuscript Accepted: 14 DEC 2007
- Manuscript Received: 28 OCT 2007
- amino acid depletion;
- loudness dependence auditory evoked potentials;
- evoked potentials
The loudness dependence of the auditory evoked potential (LDAEP) has been suggested as a possible in vivo measure of central serotonin function. However, more recent studies suggest that the LDAEP may be modulated by multiple neuromodulatory systems in addition to the serotonergic system. Accordingly we further examined the effects of selective serotonin, dopamine and simultaneous serotonin and dopamine depletion on the LDAEP in healthy subjects.
The study employed a placebo-controlled, double-blind, cross over design. Fourteen subjects were tested under four acute treatment conditions: placebo (balanced amino acid drink), tryptophan (serotonin) depletion (ATD), tyrosine/phenylalanine (dopamine) depletion (ATPD) and combined tryptophan/tyrosine/phenylalanine (serotonin and dopamine) depletion (CMD). Testing was conducted 5.5 h post-depletion and changes in the amplitude of the N1/P2 at varying intensities (60, 70, 80, 90, 100 dB) were examined at CZ.
Greater than 80% plasma precursor depletion was achieved across all conditions. Despite significant depletion of monoamine precursors, ATD, (p = 0.318), ATPD (p = 0.061) and CMD (p = 0.104) had no effects on the LDAEP (60–100 dB).
Acute serotonin and dopamine depletion did not modulate the LDAEP. This finding adds support to growing evidence that the LDAEP is insensitive to acute changes in serotonin and dopamine neurotransmission. Copyright © 2008 John Wiley & Sons, Ltd.