сигнала от рецептора к еффекторной системе: “рецептор – G-белок – обмен фосфатидилинозитидов – вторичные мессенджеры – инозит-1,4,5-трифосфат и диацилглицерин – протеинкиназа С – фосфорилирование белков”.
Таким образом, препараты сарколеммы могут быть моделью для изучения моллекулярных механизмов действия гормонов и физиологически активных веществ, которые имеют рецепторы на плазматической мембране.
Ключевые слова: миокард, сарколемма, G-белки, карбахолин, М-холинорецепторы, перфузия, фосфатидилинозитиды.
Shykula R.G. GTP-binding proteins and phosphatidylinositol cycle in muscarinic acetylcholine regulation of heart contractility. - Manuscript.
Thesis is presented for a scientific degree of the Candidate of Medical Sciences on a speciality 03.00.04 - Biochemistry. - Institute of Gerontology of Academy of Medical Sciences of Ukraine. - Kiev. - 2001.
The thesis is dedicated to the study of properties of heterotrimeric GTP-binding proteins and phosphatidylinositols interchanging in muscarinic acetylcholine receptors regulation of heart contractility. It was shown that the muscarinic cholinergic agonist carbacholine blocks the contractive miocardium function in conditions of perfusion of isolated rabbit heart. G-protein areas with high and low resemblence to binding of GTP were identified and determined their dyssociation constants for GTP. The activation of binding of GTP by carbacholine and the stimulation of GTPases activity of sarcolemma by carbacholine, were demonstrated. The isolated heart perfusion with carbacholine activates phosphatidylinositol cycle that leads to the increase of secondary messenger inositol-1,4,5-trisphosphate production. ADP-ribosylase in the presence of cough toxin and the activation of phosphatidylinositides exchange in stimulation of M-cholinergic receptors proved that functionally active Gi- and Gq-proteins are present in myocardium sarcolemma preparations.
Key words: myocardium, sarcolemma, G-proteins, carbacholine, muscarinic acetylcholine receptors, perfusion, phosphatidylinositols.