AMINO-ACID NEUROTRANSMISSION - SPOTLIGHT ON SYNAPTIC VESICLES

The vesicle hypothesis describing quantal release of neurotransmitter at the cholinergic neuromuscular junction was introduced in 19561. Since then, the concept of vesicular storage and release of acetylcholine has become firmly established2,3 and extended to include other synapses and neurotransmitters4. However, for the amino acids, which are the major class of neurotransmitters in the mammalian CNS, there was no direct experimental evidence of the participation of synaptic vesicles in neurotransmission. This area of research has now moved out of the shadows and this article discusses recent findings which indicate that amino acid neurotransmitters are accumulated and stored by synaptic vesicles in presynaptic nerve endings. © 1990.