TABLE 5.
Synaptic Structures per Type II Hair Cell, Chinchilla Crista1
Zone | Samples | Hair cells | Ribbon synapses | Afferent boutons | Efferent boutons | Outer-face ribbon synapses | Ribbon synapses per afferent bouton |
---|---|---|---|---|---|---|---|
Central | 10 | 58 | 15 ± 1 | 9 ± 1 | 3.5 ± 0.4 | 2.5 ± 0.5 | 1.8 ± 0.4 |
Intermediate | 10 | 30 | 22 ± 2 | 22 ± 3 | 4.2 ± 0.4 | 1.5 ± 0.6 | 1.0 ± 0.1 |
Peripheral | 8 | 30 | 17 ± 2 | 22 ± 2 | 2.5 ± 0.4 | 0.1 ± 0.1 | 0.8 ± 0.1 |
All | 28 | 118 | 18 ± 1 | 17 ± 2 | 3.5 ± 0.3 | 1.5 ± 0.3 | 1.2 ± 0.2 |
Samples, number of 31-section dissectors. Hair cells, equivalent number of type II hair cells in the samples. All other values, mean ± SE, number of structures per type II hair cell. The last column was obtained by taking a ratio in each sample between the number of ribbon synapses not making outer-face synapses and the number of afferent boutons. Results of an ANOVA with categorical variables as in Table 1. Zone effects: Ribbon synapses: overall (P < 0.01); C vs. I (P < 0.005); I vs. P (P < 0.02). Afferent boutons: overall (P < 0.001); C vs. I (P < 0.001); C vs. P (P < 0.005). Efferent boutons: overall (P < 0.05); I vs. P (P < 0.02). Outer-face ribbon synapses: overall (P < 0.002); C vs. P (P < 0.001); I vs. P (P < 0.02). Ribbon synapses per afferent bouton: overall (P < 0.05); C vs. I and C vs. P (P < 0.05). Axis effects: Efferent boutons: CL > CT (P < 0.02). Outer-face ribbon synapses: CL > CT (P < 0.10); IP > IB (P < 0.001).