Down Regulated Expression of the β1 Subunit of the Big-conductance Ca~(2+) Sensitive K~+ Channel in Sphincter of Oddi Cells from Rabbits Fed with a High Cholesterol Diet

摘要

Hypercholesterolemia, which is closely related to gallbladder bile stasis, can cause sphincter of Oddi dysfunction (SOD) by increasing the tension of sphincter of Oddi (SO). Intracellular calcium ion concentration ([Ca~(2+)]_i) could influence the tension of SO. The β1 subunit of the big-conductance Ca~(2+) sensitive K~+ channel (BK_(Ca)) can enhance the sensitivity of the BK_(Ca) channel to [Ca~(2+)]_i. Absence and decline of the BK_(Ca) channel subunit β1 could lead to many diseases. However, the relationship between hypercholesterolemia and the expression of β1 subunit is not well understood. In this study, we successfully expressed and purified the rabbit BK_(Ca) β1 subunit protein and prepared its polyclonal antibody. The specificity of the prepared antibody was determined by western blotting. A SOD rabbit model induced by a high cholesterol diet was established and the expression of the β1 subunit of SO was determined by immunohistochemical staining and western blotting. Compared with the controls, our results demonstrated that hypercholesterolemia could decrease the expression of the β1 subunit in the SO cells from rabbits. This indicates that lower expression of BK_(Ca) channel β1 subunit might induce SOD.