Table 2. The proportion of the nNOS positive area in the corpus of four different aged rat stomach (all, n = 6).

	6 week	31 week	74 week	2 year	P-value
The proportion of nNOS in SMB (%)	4.62 ± 3.04	4.29 ± 2.19	1.90 ± 1.43	1.99 ± 1.40	<0.001
The proportion of nNOS in CM (%)	1.60 ± 0.92	0.61 ± 0.41	0.51 ± 0.18	0.37 ± 0.22	<0.001
The proportion of nNOS in MP (%)	6.77 ±3.74	3.47 ± 2.59	3.38 ± 2.72	3.10 ± 2.41	<0.001
The proportion of nNOS in LM (%)	0.18 ± 0.16	0.24 ± 0.18	0.54 ± 0.48	0.19 ± 0.16	0.101
Total density of nNOS (%)	3.29 ± 3.56	2.12 ± 2.44	1.56 ± 1.97	1.41 ± 1.85	<0.001

The data are expressed as mean ± SD or n (%), as appropriate. The groups were compared in terms of ANOVA with post-hoc Tukey HSD in different aged rat group. SMB, submucosal border; CM, circular muscle; MP, myenteric plexus; LM, longitudinal muscle.