[Effect of vasopressin on the membrane potential of rat hepatocytes].

The current-voltage relationship of rat hepatocytes was investigated and its linear dependence was shown. On liver slices, we have investigated the effects of vasopressin on membrane potential of rat hepatocytes using microelectrode technique. Vasopressin evoked membrane hyperpolarization to -50 mV, suggesting that vasopressin activated synthetic processes in hepatocytes. Vasopressin application together with the inhibitor of protein kinase C chelerytrine also caused hyperpolarization of hepatocytes, but membrane potential changes were of smaller amplitude. This fact suggests that although protein kinase C plays an important role in the realization of effects of vasopressin, there is, however, another signal transduction pathway of vasopressin in rat hepatocytes. If that pathway activates adenylatecyclase, vasopressin can stimulate bile formation in hepatocytes. This assumption should be verified.

[Changes in ratio of lipid components in the rat bile after applying bombesin neuropeptide].

Changes of lipid components ratio in the rat bile after bombesin neuropeptide infusion (1 microg per 100 g of body weight) were studied in the acute experiment using the thin-layer chromatography. The cholates-to-cholesterol, phospholipids-to-cholesterol, cholesterol-to its esters ratios and also the potent cholesterol crystallization index were calculated and analyzed. Obtained data indicate that bombesin takes influence on the colloidal parameters of bile enhancing the secretion of phospholipids, cholesterol and its esters and free fatty acids. The peptide also intensifies cholesterol etherification and improves the colloidal stability of bile. After bombesin application the potential ability of cholesterol to crystallization remains at normal rate indicating that the useful balance of micelle forming elements is unaffected, that prevents from the development of gallstone disease.

[Effect of natural tachykinins on the bile production in rats].

We studied the changes of biligenesis and bile chemical composition under the influence of endogenous mammalian tachykinins in the acute experiments on the rats with biliary duct cannulated. We have shown that substance P, neurokinin A and neurokinin B changed volume of bile secretion and this liver reaction was accompanied by the essential changes of the bile chemical composition. Above mentioned peptides strengthen solubilisation abilities of the bile that diminishes its lithogenicity. The later is an important factor in the medical treatment of functional disturbances of the hepatobiliary system.

[Effect of substance P, neurokinin A and a selective agonist of tachykinin receptors of the NK-2 type on bile metabolism]. / Vliianie substantsii P, neirokinina A i selektivnogo agonista takhikininovykh retseptorov NK-2 tipa na zhecheobrazovanie.

Based on the experiments on rats, changes of the level of bile secretion and chemical composition of bile following application of substance P, neurokinin A, and selective agonist of the NK-2 tachykinins receptors neurokinin A Fragment (4-10), are interpreted. These results demonstrate that tachykinins (SP, NKA, and NKA Fragment (4-10)) are true holeretics and affect various enzyme systems in the hepatocyte. The alterations of the coefficients of bile confirm that.

[Bile secretion induced by L-thyroxine and substance P in dogs]. / Zhelcheotdelenie u sobak pod vliianiem L-tiroksina i substantsii P.

I.M. administration of L-thyroxin activated hepatic secretory function and changed the bile chemical contents. The substance P intensified production of bile and increased the absolute contents of free and conjugated bile acids, cholesterine, bilirubin, and total protein in the bile.