Abstract: Objective To investigate the effect of noradrenalin on the colonic mucus secretion and the distribution of β adrenoceptors in the colonic mucous cells. Methods Enzyme-linked immunosorbent assay(ELISA) was used to investigate the effect of norepinephrine(NE) on the colonic mucus secretion; immunofluorescence and laser scanning confocal microscope were used to observe the distribution of mucin2(MUC2) and β adrenoceptors in rat colonic mucosa. The mRNA expression of the β adrenoceptors in the rat colonic mucosa was analyzed by real-time PCR. Alcian blue/periodic acid schiffs(AB/PAS) staining was used to detect the distribution of mucous cells. Results NE stimulated the secretion of colonic MUC2 from(0.19±0.03) ng/mg to (0.47±0.09)ng/mg, increased by 247%. The mRNA expression of β₁ adrenoceptor and β₃ adrenoceptor was weak and β₂ adrenoceptor was the highest among the adrenoceptors expression in the colonic mucosa. Immunofluorescence staining results indicated the co-expression of MUC2 and β₂ in the colonic mucous cells. Conclusion NE is able to stimulate muc2 release from rat distal colonic mucosa.

Key words: norepinephrine, β adrenoceptor, mucin2, colon