Morphoquantitative study of the submucous plexus (of Meissner) of the jejunum-ileum of young and old guinea pigs.

OBJECTIVE To study the aging of submucous plexus of the small intestine (jejunum-ileum) of the guinea pigs from the quantitative, structural and ultrastructural perspective. METHOD Chemical preparations of membrane of the jejunum-ileum of old and young animals with the use of light and electronic microscope. RESULTS The ganglia of young animals presented between 1 and 56 neurons and the old animals presented from 1 to 30 neurons. The mean density of the ganglia by cm(2) in the young jejunum-ileum was of 551±36.89 and in the old one 413±11.86. The density of the neurons was 5011±291.11 neurons/cm(2) average in young animals and 2918±120.70 neurons/cm(2) in the old ones. The size of the neurons varied in both age groups. The collagen fibers in the ganglia of old animals they were condensed. Degenerated mitochondrias in the interior of the cell were frequent in the old animals. CONCLUSION In submucous plexus of the jejunum-ileum there is a loss of 38% of the neurons with aging.