Chemically Coded Transmitter Systems

Abstract

Publisher Summary The chemical vocabulary of interneuronal communication resides in at least three specifiable variables: the transmitter molecules that neurons secrete, the temporal and spatial domains over which interconnected cells can regulate each other, and the resultant intracellular conditions imposed by these signals on their targets. Present data indicate that molecules acting as neurotransmitters fall into three chemical classes: amino acids, amino acid derivatives, and peptides. Neuronal systems chemically coded by their transmitter substance exist within all structurally distinguishable classes of neuronal circuits. Characterization of chemical signals in the brain thus requires consideration of all three domains. The intracellular conditions imposed by the actions of transmitters on their target cells may provide the basis for a logic of intercellular operations that organizes individual neurons into responsive ensembles to produce phenomena recognizable as behavior. The ever-lengthening list of neuron-produced chemical signals allows ample possibilities for integrating time, space, and modality for rapid processing of biological information.