The aim of the study was to evaluate berberine-induced bidirectional regulation on the contractility of jejunum.
Different low and high contractile states of isolated jejunal segment from rat were established to investigate the effects of berberine.
Stimulatory effects on jejunal segment were exerted by berberine in six low contractile states and inhibitory effects were produced on jejunal segment in six high contractile states. The effects of berberine on myosin light chain kinase (MLCK) mRNA expression, MLCK protein content, and myosin phosphorylation in jejunum were also bidirectional. Bidirectional regulation was not observed in the presence of tetrodotoxin. No regulatory effects of berberine on jejunal contractility were observed in the presence of verapamil. The stimulatory effects of berberine on jejunal contractility were blocked by atropine. The inhibitory effects of berberine on jejunal contractility were abolished by phentolamine, propranolol and L-NG-nitro-arginine, respectively.
Berberine chloride (purity specification: ≥ 97%) was purchased from Chengdu Biopurify Phytochemicals Ltd, China
