B. Mahmood et al., Carbachol potentiates cholera toxin-induced secretion in a colonic epithelial cell line (HT29-19A) and rat real mucosa in vitro, J HEALTH PO, 18(1), 2000, pp. 49-53
Recent studies show that enteric nerves are involved in the action of chole
ra toxin, both in vivo and in vitro. The aim of this study was to investiga
te in vitro the influence of carbachol, a cholinergic agonist, on the actio
n of cholera toxin, Cultured HT29-19A cell lines and rat ileal mucosa were
used in an Ussing chamber for the measurement of short-circuit current indu
ced by cholera toxin, Cyclic AMP was measured from HT29-19A cell lines by s
tandard radioimmunoassay, Pre-treatment of the HT29-19A cell lines with car
bachol potentiated cholera toxin-induced secretory response, and enhanced a
ccumulation of cAMP. Carbachol also potentiated the cholera toxin-secretory
response in the rat heal mucosa, but only following pretreatment with the
prostaglandin synthesis inhibitor, indomethacin, There was synergistic inte
raction between cholera toxin and cholinergic neurotransmitter carbachol on
the intestinal epithelium, Cholinergic agonists may play a role in regulat
ing the secretory response to the toxin. Such interaction is masked in the
intact tissues in vitro due to the release of prostaglandins during isolati
on.