The inhibitory effect of exogenous nitric oxide (NO) on the open state of ATP-sensitive potassium channels (KATP) and its underlying mechanism remain unclear. In this study, patch-clamp and molecular biology techniques are used to investigate this issue. In acutely isolated rat mesenteric artery smooth muscle cells and human embryonic kidney 293 cells (HEK293) expressing inwardly rectifying potassium channel 6.1 subunit/sulfonylurea receptor 2B subunit (Kir6.1/SUR2B), sodium nitroprusside (SNP) was found to significantly inhibit the activity of open KATP channels. Detection using biotin-labeled glutathione ethyl ester (BioGEE) combined with Western blotting showed that Kir6.1 subunit glutathionylation level was significantly decreased after SNP treatment. These results indicate that exogenous NO directly inhibits the activity of open KATP channels by nitrosylating key cysteine residues of the Kir6.1 subunit and competitively inhibiting glutathionylation at this site. This study provides new experimental evidence for the molecular mechanism of NO in vascular regulation.
The construction of brain functional network based on resting-state functional magnetic resonance imaging (fMRI) is an effective method to reveal the mechanism of human brain operation, but the common brain functional network generally contains a lot of noise, which leads to wrong analysis results. In this paper, the least absolute shrinkage and selection operator (LASSO) model in compressed sensing is used to reconstruct the brain functional network. This model uses the sparsity of L1-norm penalty term to avoid over fitting problem. Then, it is solved by the fast iterative shrinkage-thresholding algorithm (FISTA), which updates the variables through a shrinkage threshold operation in each iteration to converge to the global optimal solution. The experimental results show that compared with other methods, this method can improve the accuracy of noise reduction and reconstruction of brain functional network to more than 98%, effectively suppress the noise, and help to better explore the function of human brain in noisy environment.