Skip to main content
. Author manuscript; available in PMC: 2019 Aug 2.
Published in final edited form as: J Comp Neurol. 2016 Nov 21;525(5):1216–1233. doi: 10.1002/cne.24131

Figure 5.

Figure 5.

Ultrastructure of efferent boutons in macular sensory epithelium. A: Ultrathin section of utricular macula from a wild-type (WT) mouse illustrating both afferent and efferent synaptic innervation. Afferent bouton 1 (Aff1) contains a postsynaptic density (PSD) opposite a ribbon synapse (RS) that it receives from a type II hair cell (II). Afferent bouton 2 (Aff2) is receiving a synapse indicated by the PSD, from the efferent bouton (Eff). B: Ultrathin section from the utricular macula of an α9 mouse. Similar to the case for WT mouse shown in A, a type II hair cell provides a normal-looking ribbon synapse (RS) to an afferent bouton (Aff), which contains a PSD. Efferent innervation also appears similar to the WT, with an efferent bouton (Eff) synapsing by means of a PSD on a calyx ending (Cal) surrounding a type I hair cell (I). C: In the α9 KO, an efferent bouton (Eff) making direct contact with a type II hair cell does so by means of a typical subsynaptic cistern-type synapse (SSC). Scale bars = 0.5 μm.