Glucagon-like peptide 1 improves learning and memory abilities of rats with type 2 diabetes / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of glucagon-like peptide 1 (GLP-1) on cognitive dysfunction in diabetic rats.</p><p><b>METHODS</b>Male SD rats were randomly divided into normal control group, diabetes mellitus (DM) group, and GLP-1 treatment group. Rat models of type 2 diabetes were established by high-sugar and high-fat feeding and streptozotocin (STZ) injection, and 25 days after the onset of diabetes, GLP-1 was infused in GLP-1 treatment group at the rate of 30 pmol·kg·minvia a subcutaneous osmotic pump for 7 days. The learning and cognitive ability of the rats was assessed with Morris water maze test, and the expression of cognition-related genes in the hippocampus tissue was detected with real-time PCR, Western blotting and immunohistochemical staining.</p><p><b>RESULTS</b>Compared with the normal control group, the diabetic rats showed significantly decreased learning and memory abilities (P<0.05) with increased hippocampal expressions of APP, BACE1, Arc, ERK1/2, PKA, and PKC mRNAs (P<0.05) and Arc protein. Compared with diabetic rats, GLP-1-treated rats showed significantly improvements in the learning and memory function (P<0.05) with decreased expressions of APP, BACE1, Arc, ERK1/2, and PKA mRNAs (P<0.05) and Arc protein.</p><p><b>CONCLUSION</b>GLP-1 can improve cognitive dysfunctions in diabetic rats possibly by regulating the PKC, PKA, and ERK1/2 pathways and inhibiting Arc expression in the hippocampus.</p>

Establishment of a method for determining the sphingosine kinase activity and its initial application / 中国应用生理学杂志

<p><b>AIM</b>To establish the methods for determining the activity of sphingosine kinase(SPK) and the content of sphingosine 1-phosphate (S1P) in biological samples.</p><p><b>METHODS</b>The ECV304 cells were transfected with pcDNA3 vector encoding Flag-labeled SPK gene. The expression of SPK was measured by Western blot assay and the activity of SPK was determined by enzymatic reaction, isotope incorporation and thin-layer chromatography methods. The S1P in biological samples was extracted, digested by alkaline phosphatase and then catalyzed by SPK. The S1P contents were determined according to the amounts of products.</p><p><b>RESULTS</b>SPK gene transfection could enhance the expression and activity of SPK in cells markedly, and the cellular S1P was also increased obviously. HGF stimulation could increase the activity of SPK and cellular S1P in ECV304 cells.</p><p><b>CONCLUSION</b>Methods for determining the activity of SPK and the content of SPK in biological samples were established.</p>