Cholinergic responsiveness of goblet cells during intestinal maturation

In adult rat intestine, cholinergic stimulation accelerates discharge of mucus from crypt, but not villus, goblet cells. It was not known whether goblet cells in fetal or suckling rats are cholinergically sensitive. Rat pups (20 days of gestation to 30 postnatal days) were given subcutaneous injections of carbachol and the intestines were fixed 5 min later. Accelerated mucus secretion was assessed by light microscopy of semithin plastic sections. Goblet cells in ileal and colonic crypts did not show an adult-like response until 20-25 days after birth. Ileal and colonic mucosal explants in vitro showed age-dependent responses identical to those observed in vivo. The onset of cholinergic sensitivity occurred well after the formation of crypts and was always limited to crypt goblet cells.