Taurine relaxes human radial artery through potassium channel opening action

The vascular actions and mechanisms of taurine were investigated in the isolated human radial artery (RA). RA rings were suspended in isolated organ baths and tension was recorded isometrically. First, a precontraction was achieved by adding potassium chloride (KCl, 45 mM) or serotonin (5-hydroxytryptamine, 5-HT, 30 µM) to organ baths. When the precontractions were stable, taurine (20, 40, 80 mM) was added cumulatively. Antagonistic effect of taurine on calcium chloride (10 µM to 10 mM)-induced contractions was investigated. Taurine-induced relaxations were also tested in the presence of the K⁺ channel inhibitors tetraethylammonium (1 mM), glibenclamide (10 µM) and 4-aminopyridine (1 mM). Taurine did not affect the basal tone but inhibited the contraction induced by 5-HT and KCl. Calcium chloride-induced contractions were significantly inhibited in the presence of taurine (20, 40, 80 mM) (p<0.05). The relaxation to taurine was inhibited by tetraethylammonium (p<0.05). However, glibenclamide and 4-aminopyridine did not affect taurine-induced relaxations. Present experiments show that taurine inhibits 5-HT and KCl-induced contractions in RA, and suggest that large conductance Ca²⁺-activated K⁺ channels may be involved in taurine-induced relaxation of RA.

Casein/natamycin edible films efficiency for controlling mould growth and on microbiological, chemical and sensory properties during the ripening of Kashar cheese.

BACKGROUND: The objective of the present study was to investigate the effects of the dipping application of coating materials such as casein (Cas), casein/natamycin (Cas/N) and natamycin (N) solutions on chemical (e.g. pH, dry matter, fat, acidity, salt, protein, water-soluble nitrogen, ripening index, 12% trichloroacetic acid-soluble nitrogen and pH 4.6 soluble nitrogen), microbial (e.g. total number of aerobic mesophilic bacteria, lactic acid bacteria in MRS, lactic acid bacteria in M17, coliforms and mould) and organoleptic properties of Kashar cheese samples during ripening (3, 30, 60 and 90 days). RESULTS: The difference in microbiological and chemical changes between samples were found to be significant (P < 0.05) during the ripening period. The highest and lowest mould counts were determined for the control (2.87 log cfu g(-1) ) and the Cas/N (<1 log cfu g(-1) ) samples, respectively, at 90 days of ripening. Compared to other cheeses, control and Cas/N-coated cheeses had higher levels of water-soluble nitrogen and ripening index at in the end of storage. The Cas/N-coated cheese samples were preferred more by the panellists, while N-coated cheese samples received the lowest scores. CONCLUSION: This study suggests that coating could be used to improve the quality of Kashar cheese during ripening.