Skip to main content

High dose glycine inhibits the loudness dependence of the auditory evoked potential (LDAEP) in healthy humans

Journal Article


Abstract


  • RATIONALE: The loudness dependence of the auditory evoked Potential (LDAEP) has been suggested to be a putative marker of central serotonin function, with reported abnormalities in clinical disorders presumed to reflect serotonin dysfunction. Despite considerable research, very little is known about the LDAEP's sensitivity to other neurotransmitter systems. OBJECTIVES: Given the role of N-methyl-D-aspartate (NMDA) receptors in modulating pyramidal cell activity in cortico-cortico and thalamo-cortical loops, we examined the effect of targeting the glycine modulatory site of the NMDA receptor with high-dose glycine on the LDAEP in healthy subjects. MATERIALS AND METHODS: The study was a double-blind, placebo-controlled repeated-measures design in which 14 healthy participants were tested under two acute treatment conditions, placebo and oral glycine (0.8 g/kg). Changes in the amplitude of the N1/P2 at varying intensities (60, 70, 80, 90, 100 dB) were examined at C(Z). RESULTS: Compared to placebo, high-dose glycine induced a weaker LDAEP (a pronounced decrease in the slope of the N1/P2 with increasing tone loudness; p < 0.02). CONCLUSION: While the exact mechanism responsible for the effects of glycine on the LDAEP are not known, the findings suggest an inhibitory effect in the cortex, possibly via activation of NMDA receptors on GABA interneurons or inhibitory glycine receptors. The findings add to the growing literature exhibiting modulation of the LDAEP by multiple neurochemical systems in addition to the serotonergic system.

Authors


  •   O'Neill, Barry V. (external author)
  •   Croft, Rodney J.
  •   Leung, Sumie (external author)
  •   Oliver, Chris (external author)
  •   Phan, KL (external author)
  •   Nathan, Pradeep J. (external author)

Publication Date


  • 2007

Citation


  • O'Neill, B. V., Croft, R. J., Leung, S., Oliver, C., Phan, K. Luan. & Nathan, P. J. (2007). High dose glycine inhibits the loudness dependence of the auditory evoked potential (LDAEP) in healthy humans. Psychopharmacology, 195 (1), 85-93.

Scopus Eid


  • 2-s2.0-35248833040

Ro Metadata Url


  • http://ro.uow.edu.au/hbspapers/3318

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 85

End Page


  • 93

Volume


  • 195

Issue


  • 1

Abstract


  • RATIONALE: The loudness dependence of the auditory evoked Potential (LDAEP) has been suggested to be a putative marker of central serotonin function, with reported abnormalities in clinical disorders presumed to reflect serotonin dysfunction. Despite considerable research, very little is known about the LDAEP's sensitivity to other neurotransmitter systems. OBJECTIVES: Given the role of N-methyl-D-aspartate (NMDA) receptors in modulating pyramidal cell activity in cortico-cortico and thalamo-cortical loops, we examined the effect of targeting the glycine modulatory site of the NMDA receptor with high-dose glycine on the LDAEP in healthy subjects. MATERIALS AND METHODS: The study was a double-blind, placebo-controlled repeated-measures design in which 14 healthy participants were tested under two acute treatment conditions, placebo and oral glycine (0.8 g/kg). Changes in the amplitude of the N1/P2 at varying intensities (60, 70, 80, 90, 100 dB) were examined at C(Z). RESULTS: Compared to placebo, high-dose glycine induced a weaker LDAEP (a pronounced decrease in the slope of the N1/P2 with increasing tone loudness; p < 0.02). CONCLUSION: While the exact mechanism responsible for the effects of glycine on the LDAEP are not known, the findings suggest an inhibitory effect in the cortex, possibly via activation of NMDA receptors on GABA interneurons or inhibitory glycine receptors. The findings add to the growing literature exhibiting modulation of the LDAEP by multiple neurochemical systems in addition to the serotonergic system.

Authors


  •   O'Neill, Barry V. (external author)
  •   Croft, Rodney J.
  •   Leung, Sumie (external author)
  •   Oliver, Chris (external author)
  •   Phan, KL (external author)
  •   Nathan, Pradeep J. (external author)

Publication Date


  • 2007

Citation


  • O'Neill, B. V., Croft, R. J., Leung, S., Oliver, C., Phan, K. Luan. & Nathan, P. J. (2007). High dose glycine inhibits the loudness dependence of the auditory evoked potential (LDAEP) in healthy humans. Psychopharmacology, 195 (1), 85-93.

Scopus Eid


  • 2-s2.0-35248833040

Ro Metadata Url


  • http://ro.uow.edu.au/hbspapers/3318

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 85

End Page


  • 93

Volume


  • 195

Issue


  • 1