Synaptic plasticity has been studied extensively because of its potential connection with learning and memory. However, nearly all experiments have hitherto focused on questions concerning changes in the release probability of neurotransmitter or on changes on the postsynaptic side of the synapse, e.g., the number or the sensitivity of neurotransmitter receptors.
Engel et al. examined whether the strength of inhibitory synapses could be regulated through changes in the metabolism of the neurotransmitter GABA. By interfering with the activity of the major degradative and synthetic enzymes for GABA, they could increase or decrease both the size and frequency of miniature GABAergic postsynaptic currents. They conclude that the machineries for filling vesicles with neurotransmitter, for vesicle release, and for postsynaptic response do not work at maximal load and can thus be finely tuned through changes in presynaptic GABA concentration. This would give the nervous system additional flexibility when varying synaptic strength. -- PRS
J. Physiol. 535, 473 (2001).
