This article is concerned with the discovery that amino acids, particularly
L-glutamate and gamma-aminobutyrate (GABA), are central neurotransmitters.
The crucial observations that lead to the conclusion that these two amino
acids produce most of the synaptic excitation and inhibition in the central
nervous system, were made in late 1950's. The combination of neurochemical
knowledge and improved electrophysiological techniques was paramount in ma
king these discoveries possible. In particular, the use of specific antagon
ists in microiontophoretic experiments provided the most decisive evidence.
The relationship is also explored between these early findings and those o
f the present era characterised by extensive use of techniques of molecular
biology and the development of drugs against targets identified 30 to 40 y
ears ago. (C) 1999 Elsevier Science Ltd. All rights reserved.