Prikhodko T. The mechanisms of vasomotor effects of Acetylcholine on hepatic venous vessels

The objectives of PhD progect is to elucidate the vasomotor effects of acetylcholine (Ach) on liver venous vessels (portal and hepatic veins). In acute experiments on the anesthetized rats (ure-tan - 1g/kg) the blood pressure in carotid artery (AP) and in por-tal vein (PV), and changes of the liver blood volume (LBV) were registrated after intraportal administration of Ach. It has been established, that the Ach caused the constriction of the liver por-tal vessels and the decrease of liver blood volume. Vasoconstrict-ing effects of Ach on capacitive liver vessels are removed by the blockade of М- cholino - and alfa-adrenoreceptors. It was shown that the portal vessels (PV) did not take part in reactions of the liver blood filling. Ach induced the tonic constriction of the por-tal vessels in the isolated sumples, which is mediated by the acti-vation of M-cholinoreceptors, possibly, with further involvement of noradrenaline as a hypothesized mediator that activates alfa-adrenoreceptors in smooth musculecells of these vessels and cause its constructions. It was shown that N-cholin- and endote-linreceptors of A-type also partly mediated these reactions. In addition, the outgoing system of hepatic veins (HV) was investi-gated. It was found that the sphincter area of HV responded on Ach action by the relaxation. Such Ach effect in this area was realized by the activation of beta1- adrenoreceptors. Presphincter part of liver vessels responded on Ach action by the tonic con-striction, which involved alfa-adrenoreceptors.