Phosphorylation of phosphatidylinositides during muscarinic acetylcholine receptor regulation of myocardium contraction.
While estimating the myocardium sarcolemma phosphatidylinositides phosphorylation the muscarime acetylcholine receptor agonist carbacholine (10(-7) M) was determined as capable to stimulate 32P incorporation into phosphatidylinositol-4-monophosphate (in 2.6 times) and phosphatidylinositol-4,5-bisphosphate (in 2.3 times) indicating to the activation of phosphatidylinosite kinase and phosphatidylinosite 4-kinase respectively. The phosphorylation reactions in general completely depend on the presence in the incubation medium of Mg2+ capable in 10 mkM concentration to increase 32P influx into phosphatidylinositol-4-monophosphate 8 times, and into phosphatidylinositol-4,5-bisphosphate 4 times. Carbacholine (10(-7) M) also activates phospholipase C which hydrolyses phosphatidylinositol-4,5-bisphosphate. The latter is substantiated by the increase (2.6 times) of the secondary messenger--inositol-1,4,5-trisphosphate formation.
Kalinski
M I
MI
Kent State University, USA. mkalinsk@kent.edu
Vorobets
Z D
ZD
Kurski
M D
MD
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D004789:Enzyme Activation; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D010766:Phosphorylation; D011817:Rabbits; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012508:Sarcolemma / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D010738:Type C Phospholipases / Q000187:drug effects / Q000378:metabolism
D018679:Cholinergic Agonists; D018129:Phosphatidylinositol Phosphates; D011976:Receptors, Muscarinic; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D010738:Type C Phospholipases; D008274:Magnesium