Table 3.
Main Effects of Age and Training on Neuromuscular Junctions in the Medial Thyroarytenoid Muscle
| Young | Old | Control | Trained | |
|---|---|---|---|---|
| Presynaptic remodelling | ||||
| Axon withdrawal (%)* | 18.5±3.6 | 15.2±3.5 | 15.6±3.8 | 18.1±3.3 |
| Axon sprouts (%) | 2.7±0.8 | 5.2±1.6 | 4.7±1.3 | 3.2±1.2 |
| Terminal Schwann cell processes (%) | 8.6±1.5 | 17.8±2.8† | 15.9±2.8 | 10.5±1.9 |
| Size and pre/postrelationship | ||||
| Nerve terminal volume (µm3) | 88.8±10.0 | 127.5±9.1† | 104.0±8.9 | 112.3±11.9 |
| Motor endplate volume (µm3) | 101.9±4.0 | 116.3±4.4† | 105.5±4.9 | 112.7±4.0 |
| Overlap (%) | 64.8±4.9 | 71.1±4.2 | 70.1±4.5 | 65.8±4.6 |
| Endplate stability | ||||
| Dispersion (%) | 8.5±0.5 | 12.0±0.7† | 10.6±0.7 | 9.9±0.7 |
| Fragmented endplates (%)‡ | 19.9±2.1 | 34.2±2.6† | 25.2±2.1 | 28.9±3.4 |
Notes: Values are means ± SE; n = 40 (20 per group).
*Nonparametric testing completed due to heteroskedasticity.
†Significant difference (p ≤ .05) from young group.
‡Log transformed to achieve homoskedasticity; values shown untransformed.