Cysteine: depolarization-induced release from rat brain in vitro.
Compounds released on depolarization in a Ca2+-dependent manner from rat brain slices were screened to identify candidates for neuroactive substances. Lyophilized superfusates were analyzed by reversed-phase HPLC after derivatization with 9-fluorenyl N-succinimidyl carbonate. One of the compounds that showed an increase of concentration in superfusates in the presence of iodoacetamide was identified as the cysteine (Cys) derivative, S-carboxamidomethylcysteine, by fast atom bombardment mass spectrometry and other methods. This stable Cys derivative originates from endogenous, extracellular Cys. The finding led to a method for quantification of Cys in superfusates by immediate cooling of the superfusates to 0 degrees C and reaction of Cys with N-ethylmaleimide. Depolarization-induced Ca2+-dependent release of Cys was most prominent in the neocortex, followed by the mesodiencephalon, striatum, and cerebellum. This suggests that Cys is released from a neuronal compartment and might be involved in neurotransmission.
Keller
H J
HJ
Brain Research Institute, University of Zürich, Switzerland.
Do
K Q
KQ
Zollinger
M
M
Winterhalter
K H
KH
Cuénod
M
M
D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000032:analysis / Q000378:metabolism*; D004594:Electrophysiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D003545:Cysteine