Stereologic evaluation of the pig gastric wall and of somatostatinergic and serotoninergic immunoreactive mucosal cells during perinatal development.

A quantitative morphological study using stereologic methods was performed on vertical paraffin sections of the stomach of fetal and neonatal pigs. The sections were processed for 5-HT- and SOM-immunohistochemistry. In the neonatal pigs, the volume density of the submucosal layer in the pyloric gland region was approximately 15% less compared to the cardiac gland region. This suggests that altered functional demands after birth are temporarily related to and perhaps could promote the morphological diversification between the gastric regions. The distribution of 5-HT-IR and SOM-IR mucosal cells corresponds with previous observations in the adult mammalian stomach. However, based upon our results an age-dependent maturity or even different role is suspected for 5-HT and SOM. This is substantiated by the 4-fold rise of the volume occupied by 5-HT-IR mucosal cells in the pyloric gland region during development. Secondly, the regional differences of the volume density of SOM-IR mucosal cells vary according to developmental stage. The developmental variations of 5-HT- and SOM-IR mucosal cells contrast with findings in the rodent stomach. However, they are comparable to observations in man.