(A) Synapse number between cone bipolar cells (CBC) and ganglion cells (RGC) is regulated by neurotransmission. Type 6 bipolar cells that express tetanus toxin (TeNT) make fewer synapses with dendrites of large-field ON alpha-like ganglion cells compared to wildtype (WT) bipolar cells (Kerschensteiner et al., 2009; Morgan et al., 2011; Okawa et al., 2014).
(B) GABAergic neurotransmission is necessary for maintaining specific GABA receptor subtypes on rod bipolar cell (RBC) axon terminals. Impairing inhibitory neurotransmission from amacrine cells (ACs) in the GAD67 (GABA synthetic enzyme) deficient (GAD1 mutant) retina leads to a reduction in GABAA but not GABAC receptors on RBC axon terminals (Schubert et al., 2013).