Identification and quantitation of N-acetyl metabolites of biogenic amines in the thoracic nervous system of the locust, Schistocerca gregaria, by gas chromatography-negative-ion chemical ionisation mass spectrometry.
The N-acetylated metabolites of p-tyramine, p-octopamine and dopamine were identified unambiguously and quantitatively determined in a single ventral thoracic nerve cord of the locust, Schistocerca gregaria, by gas chromatography-negative-ion chemical ionisation mass spectrometry (GC-NICIMS). Deuterium-labelled analogues of each compound were added to a single ventral thoracic nerve cord in acetonitrile: the tissue was homogenised and the suspension centrifuged. The solvent was removed from the supernatant and the resultant residue was derivatised with trifluoroacetic anhydride. Under negative-ion chemical ionisation conditions, the trifluoroacetyl derivatives produced ions which were sufficiently abundant to be suitable for selected-ion monitoring. This method is highly specific and gave a limit of detection below the picogram levels. N-Acetyl-5-hydroxytryptamine was determined using a previously published GC-NICIMS technique [S.P. Markey, R.W. Colburn and J.N. Johannessen, Biomed. Mass Spectrom., 7 (1981) 301]. The concentrations of N-acetyltyramine, N-acetyloctopamine, N-acetyldopamine and N-acetyl-5-hydroxytryptamine in locust thoracic nerve cords were, respectively, 1.86 +/- 0.71, 1.13 +/- 0.34, 6.77 +/- 8.48 and 0.07 +/- 0.02 ng per tissue.
Macfarlane
R G
RG
Department of Pharmacy, University of Strathclyde, Glasgow, Scotland, U.K.
Midgley
J M
JM
Watson
D G
DG
Evans
P D
PD
D000089:Acetic Anhydrides; D000107:Acetylation; D000818:Animals; D015306:Biogenic Monoamines / Q000032:analysis* / Q000737:chemistry; D003903:Deuterium; D004298:Dopamine / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry; D005463:Fluoroacetates; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006110:Grasshoppers; D015394:Molecular Structure; D009420:Nervous System / Q000737:chemistry*; D009655:Octopamine / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry; D013909:Thorax; D014439:Tyramine / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry
D000089:Acetic Anhydrides; D015306:Biogenic Monoamines; D005463:Fluoroacetates; D009655:Octopamine; C006374:N-acetyldopamine; C028483:N-acetyloctopamine; C017958:trifluoroacetic anhydride; D003903:Deuterium; C054479:N-acetyltyramine; D004298:Dopamine; D014439:Tyramine