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Application of Stable Isotope Tracer Combined with Mass Spectrometric Detection for Studying myo ‐Inositol Uptake by Cultured Neurons from Fetal Mouse: Effect of Trisomy 16
Author(s) -
Acevedo Larisa D.,
Holloway Harold W.,
Rapoport Stanley I.,
Umesha Shetty H.
Publication year - 1997
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199704)32:4<395::aid-jms487>3.0.co;2-#
Subject(s) - inositol , chemistry , mass spectrometry , biochemistry , chromatography , receptor
A gas chromatographic (GC)/mass spectrometric method for studying myo ‐inositol uptake by neurons in vitro is described. Cultured cortical neurons from fetuses of diploid and trisomy 16 mouse (animal model for Down syndrome) were incubated with a physiological concentration of hexadeuterated myo ‐inositol for 2–40 min. Washed cells were lysed and scyllo ‐inositol (internal standard) was added to the intracellular material which contained labeled myo ‐inositol taken up by the cells as well as the endogenous, unlabeled myo ‐inositol. The samples were evaporated to dryness and the analytes were converted into acetate derivatives. The components were separated by capillary GC, and the m / z 379 ion for labeled myo ‐inositol and the m / z 373 ion for myo ‐inositol and scyllo ‐inositol generated by chemical ionization in an ion trap mass spectrometer were monitored. Quantitation of the deuterium‐labeled myo ‐inositol taken up by the neuron along with endogenous myo ‐inositol was achieved for 2–40 min of incubation. The labeled myo ‐inositol uptake was linear for up to 20 min and was Na + dependent in these neurons. This non‐radioisotope method was used to demonstrate a significant (40%) increase in the rate of myo ‐inositol uptake by cortical neurons from the trisomy 16 mouse relative to control neurons. An increased myo ‐inositol uptake is consistent with evidence that the myo ‐inositol transporter gene is on both human chromosome 21 and mouse chromosome 16, and that myo ‐inositol concentrations are elevated in cerebrospinal fluid from adult Down syndrome individuals and brains from the fetal trisomy 16 mouse. © 1997 by John Wiley & Sons, Ltd.