title: Effects of the N-methyl-D-Aspartate receptor antagonist dextromethorphan on vibrotactile adaptation.
abstract: BACKGROUND
  Previous reports have demonstrated that short durations of vibrotactile stimuli (less than or equal to 2 sec) effectively and consistently modify both the perceptual response in humans as well as the neurophysiological response in somatosensory cortex. The change in cortical response with adaptation has been well established by a number of studies, and other reports have extended those findings in determining that both GABA- and NMDAR-mediated neurotransmission play a significant role in the dynamic response of somatosensory cortical neurons. In this study, we evaluated the impact that dextromethorphan (DXM), an NMDAR antagonist, had on two distinct vibrotactile adaptation tasks.
  
  
  RESULTS
  All subjects, both those that ingested 60 mg DXM and those that ingested placebo, were evaluated for their amplitude discriminative capacity between two simultaneously delivered vibrotactile stimuli both with and without 3 conditions of pre-exposure to adapting stimulation. The results demonstrated that the perceptual metrics of subjects who ingested 60 mg DXM were significantly altered from that of controls when the amplitude discrimination task followed one of the conditions of adapting stimulation. Without the condition of pre-exposure to an adapting stimulus (or stimuli), there was little difference between the observations obtained from the subjects that ingested DXM and controls. Peak impact on subject response occurred at 60 min post-ingestion, whereas the scores of controls who ingested placebo were not impacted.
  
  
  CONCLUSIONS
  The results - that DXM blocks vibrotactile adaptation - is consistent with the suggestion that NMDAR-mediated neurotransmission plays a significant role in the perceptual adaptive response. This finding is also consistent with neurophysiological findings that report observations of the effects of NMDAR block on the SI cortical response to repetitive vibrotactile stimulation.
authors.affiliation: Department of Physical Therapy Education, Elon University, Elon, NC 27244, USA. folgers@elon.edu
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Folger
authors.forename: Vinay
authors.initials: V
authors.lastname: Tannan
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jameson K
authors.initials: JK
authors.lastname: Holden
authors.forename: Mark
authors.initials: M
authors.lastname: Tommerdahl
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000328:Adult; D003915:Dextromethorphan / Q000008:administration & dosage / Q000494:pharmacology*; D004192:Discrimination, Psychological / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D010470:Perceptual Masking / Q000502:physiology; D010812:Physical Stimulation / Q000379:methods; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D012684:Sensory Thresholds / Q000187:drug effects / Q000502:physiology; D013003:Somatosensory Cortex / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D014110:Touch / Q000502:physiology; D014732:Vibration
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D003915:Dextromethorphan
references.citation: Cereb Cortex. 1992 Mar-Apr;2(2):107-33
references.pmid: 1633410
references.citation: J Neurosci. 2004 Oct 20;24(42):9228-31
references.pmid: 15496656
references.citation: Brain Res. 1998 Jun 15;796(1-2):82-90
references.pmid: 9689457
references.citation: J Neurophysiol. 1994 Oct;72(4):1706-16
references.pmid: 7823096
references.citation: J Neurosci Methods. 2007 Aug 15;164(1):131-8
references.pmid: 17537516
references.citation: Sens Processes. 1979 Mar;3(1):37-48
references.pmid: 515739
references.citation: J Autism Dev Disord. 2001 Apr;31(2):247-8
references.pmid: 11450824
references.citation: J Neurophysiol. 1999 Jun;81(6):2988-3006
references.pmid: 10368415
references.citation: Brain Res. 1999 Jan 9;815(2):326-36
references.pmid: 9878812
references.citation: Behav Brain Funct. 2005 Oct 10;1:18
references.pmid: 16216121
references.citation: Behav Brain Funct. 2007 Dec 04;3:61
references.pmid: 18053216
references.citation: Autism Res. 2008 Aug;1(4):223-30
references.pmid: 19360672
references.citation: Brain Res. 2007 Dec;1186:164-70
references.pmid: 18005946
references.citation: Somatosens Mot Res. 1990;7(2):205-21
references.pmid: 2378193
references.citation: J Neurophysiol. 1982 Apr;47(4):677-99
references.pmid: 7069461
references.citation: J Neurophysiol. 2007 May;97(5):3155-64
references.pmid: 17344377
references.citation: Brain Res. 2007 Jun 18;1154:116-23
references.pmid: 17498672
references.citation: Sens Processes. 1977 Aug;1(4):292-300
references.pmid: 918678
references.citation: Brain Res. 1989 Jan 30;478(2):356-60
references.pmid: 2538204
references.citation: Ment Retard Dev Disabil Res Rev. 2004;10(4):303-17
references.pmid: 15666334
references.citation: Science. 2003 Jul 4;301(5629):91-4
references.pmid: 12843392
references.citation: Cereb Cortex. 1992 Mar-Apr;2(2):81-106
references.pmid: 1633418
references.citation: Behav Brain Funct. 2008 Apr 24;4:19
references.pmid: 18435849
references.citation: Behav Brain Res. 2002 Sep 20;135(1-2):119-26
references.pmid: 12356441
references.citation: J Neurophysiol. 1988 Feb;59(2):607-22
references.pmid: 3351576
references.citation: Brain Res. 2006 Aug 2;1102(1):109-16
references.pmid: 16806126
references.citation: Int Rev Neurobiol. 2005;71:167-78
references.pmid: 16512350
references.citation: Clin Genet. 2007 Jul;72(1):1-8
references.pmid: 17594392
references.citation: J Neurosci Methods. 2005 Sep 30;147(2):75-81
references.pmid: 15970331