Glycine as a neurotransmitter in the forebrain: a short review.

Since the late 1970s glycine has been considered an important inhibitory neurotransmitter in brain stem and medulla. The description of its involvement in the mechanism of action of the potent neurotoxin strychnine pushed further the concept of inhibitory transmitter. The significant concentrations of glycine in forebrain motivated investigators to evaluate different aspects of glycinergic transmission under the ontogenetic, physiologic and pathologic standpoints. This review encompasses a few of these aspects as the role of the different glycine receptors (GlyRs) in intracellular chloride balance, glycine transporters, GABA/Glycine co-release, glycine/NMDA receptor interaction, glycine receptors in acute alcohol effects and advocates a more relevant role for glycine as a stimulatory transmitter in forebrain areas. Finally, the possible co-release of glycine and GABA is considered as an important process to understand the role of glycine in forebrain neural transmission.