The expression of this LTP involves presynaptic changes and requires AA signaling. Here, we demonstrate that excitatory synapses in the retina can undergo activity-dependent long-term synaptic plasticity. The absence of evidence for LTP in the retina had previously led to the idea that the lack Talazoparib of long-term synaptic plasticity helps the stability of visual processing
in the retina. In recent years there are scattered studies showing that synapses in both adult and developing retinae are capable of undergoing long-lasting functional changes in response to intensive stimulation. In the adult goldfish retina, the transmission of reciprocal inhibitory synapses formed by amacrine cells
Volasertib order on BCs exhibits depolarization-induced enhancement for up to 10 min (Vigh et al., 2005). During the critical period of visual system development, the trafficking of AMPARs at mouse and rat BC-RGC synapses can be regulated by light illumination (Xia et al., 2006, 2007). In developing Xenopus tadpoles, long-term changes in synaptic AMPAR function at RGC dendrites can be induced by retrograde signaling from the optic tectum to retina ( Du and Poo, 2004; Du et al., 2009). Our present work directly demonstrates that during development, transmission of BC-RGC synapses in the zebrafish retina can be persistently potentiated by both repeated electrical and visual stimulations. This LTP is similar to the typical LTP found in central brain regions in both the time course and postsynaptic NMDAR dependency ( Lynch, 2004; Malenka and Bear,
2004). In the developing zebrafish retina, LTP can be induced at both ON and OFF inputs of ON-OFF, ON, and OFF RGCs. First, repetitive flash stimuli could induce LTP at BC-RGC synapses in all three subtypes of RGCs (six ON-OFF cells, one ON cell, and two OFF cells). Second, TBS could induce persistent enhancement of both ON (nine out of nine) and OFF (three out of eight) light responses among one ON and eight ON-OFF RGCs. Third, RFS could induce persistent enhancement of both ON (nine out of ten) and OFF (five out of eight) light responses in RGCs. Please note that these data suggest that ON synapses 3-mercaptopyruvate sulfurtransferase on RGCs are more prone to undergo potentiation than OFF synapses. In mammals some subtypes of RGCs do not undergo dramatic developmental remodeling of their dendritic processes, but others do (Kim et al., 2010), implying that synaptic activity-induced LTP may only occur at some subtypes of RGCs. Transmitter release at the BC-RGC excitatory synapse, a typical ribbon synapse possessing high rates of exocytosis for transmitting graded potentials, is highly regulated (Sterling and Matthews, 2005; von Gersdorff et al., 1998; Wässle, 2004) by reciprocal inhibition from amacrine cells (Du and Yang, 2000; Vigh et al.