LONG-TERM REGULATION OF SHORT-TERM PLASTICITY - A POSTSYNAPTIC INFLUENCE ON PRESYNAPTIC TRANSMITTER RELEASE

The dynamics of presynaptic transmitter release are often matched to t he physiological properties and function of the postsynaptic cell. Evi dence in organisms as diverse as the cricket central nervous system an d the cat spinal cord suggests that retrograde signaling is essential for matching presynaptic release properties to the postsynaptic cell. The cricket central nervous system is favorably organized for analysis of synaptic function in the central nervous system. Several lines of independent evidence suggest that it is possible to reliably estimate the size of single quantal release events at the sensory to interneuro n synapses of the cricket. A quantal analysis suggests that a retrogra de influence on the probability of presynaptic release is responsible for matching presynaptic dynamic properties to postsynaptic targets. T his retrograde interaction is hypothesized to be a long-term modificat ion on the basal probability of presynaptic release.