. Author manuscript; available in PMC: 2011 May 1.

Published in final edited form as: Exp Gerontol. 2010 Mar 11;45(5):389–393. doi: 10.1016/j.exger.2010.03.007

Table 2.

Neuromuscular junction morphology in young, and aged plantaris muscles

	Fast-twitch		Slow-twitch
Pre-synaptic	Young (N=10)	Aged (N=10)	Young (N=9)	Aged (N=9)
Branch number	5.8 ± 0.3	6.7 ± 0.3^†	5.5 ± 0.5	6.9 ± 0.3^†
Total branch length (μm)	192.3 ± 11.9	255.4 ± 11.9^*	190.7 ± 15.1	248.2 ± 11.0^*
Average branch length (μm)	33.2 ± 2.0	38.1 ± 1.4^*	36.7 ± 2.0	35.9 ± 2.3
Branching complexity	11.2 ± 1.3	17.1 ± 1.6^*	10.8 ± 1.8	16.5 ± 3.1^*
Post-synaptic
Total perimeter (μm)	118.4 ± 9.8	151.9 ± 13.5^*	123.8 ± 7.6	154.2 ± 6.9^*
Stained perimeter (μm)	216.6 ± 13.9	321.8 ± 16.2^*	248.8 ± 32.4	334.4 ± 28.2^*
Total area (μm²)	685.4 ± 58.4	992.8 ± 76.8^*	743.6 ± 89.8	954.3 ± 83.6^*
Stained area (μm²)	548.1 ± 37.1	795.8 ± 61.0^*	581.2 ± 67.9	758.7 ± 80.5^*
Dispersion (%)	80.0 ± 2.4	78.1 ± 1.6	78.2 ± 2.7	79.4 ± 2.0
Pre-to post- synaptic coupling	2.9 ± 0.6	3.1 ± 0.2	3.0 ± 0.6	3.1 ± 0.2

Values are means ± SE. Branching complexity = branch number x total branch length/100. Dispersion = stained area/total area. Pre- to post-synaptic coupling = endplate stained area/total nerve terminal branch length.

^†

indicates trend (0.05 < P < 0.10) for significant difference from Young.

indicates significant (P < 0.05) difference from Young.