Capillary electrophoresis combined with microdialysis in the human spinal cord: a new tool for monitoring rapid peroperative changes in amino acid neurotransmitters within the dorsal horn.
A method originally developed for the separation of the three neurotransmitters gamma-aminobutyric acid (GABA), glutamate (Glu) and L-aspartate (L-Asp) in microdialysis samples from rat brain (Sauvinet et al., Electrophoresis 2003, 24, 3187-3196) was applied to human spinal dialysates obtained during peroperative microdialysis from patients undergoing surgery against chronic pain. Molecules were tagged on their primary amine function with the fluorogene agent, naphthalene-2,3-dicarboxaldehyde (NDA), and, after separation by capillary electrophoresis (CE, 75 mmol/L borate buffer, pH 9.2, containing 70 mmol/L sodium dodecyl sulfate and 10 mmol/L hydroxypropyl-beta-cyclodextrin, + 25 kV voltage), were detected by laser-induced fluorescence detection (LIFD) using a 442 nm helium-cadmium laser. The complete method, including microdialysis sampling and analysis by CE-LIFD, has been validated for the analysis of human spinal microdialysates. The analytical detection limits were 1, 3.7 and 17 nmol/L for GABA, Glu and L-Asp respectively. This method allows an accurate measurement of the three amino acid neurotransmitters during an in vivo monitoring performed as rapidly as every minute in the human spinal dorsal horn. In addition, the effect of a brief peroperative electrical stimulation of the dorsal rootlets was investigated. The results obtained illustrate the advantages of combining microdialysis with CE-LIFD for studying neurotransmitters with such a high sampling rate.
Parrot
Sandrine
S
IFR 19, Institut Fédératif des Neurosciences de Lyon, Hôpital Neurologique, and Université Claude Bernard, 8 avenue Rockefeller, F-69373 Lyon Cedex 08, France. sparrot@rockefeller.univ-lyon1.fr
Sauvinet
Valérie
V
Xavier
Jean-Michel
JM
Chavagnac
Delphine
D
Mouly-Badina
Laurence
L
Garcia-Larrea
Luis
L
Mertens
Patrick
P
Renaud
Bernard
B
D001224:Aspartic Acid / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods; D018698:Glutamic Acid / Q000032:analysis*; D006801:Humans; D017551:Microdialysis / Q000379:methods; D009281:Naphthalenes; D020671:Posterior Horn Cells / Q000378:metabolism* / Q000601:surgery; D013116:Spinal Cord / Q000378:metabolism* / Q000601:surgery; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
D009281:Naphthalenes; D001224:Aspartic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; C027717:2,3-naphthalenedicarboxaldehyde