Vlivy cholesterolu na dynamiku chování acetylcholinových muskarinových receptorů buněčné membrány

• Main Author: Michal, Pavel
• Other Authors: Semecký, Vladimír
• Format: Dissertation
• Language: Czech
• Published: 2011
• Online Access: http://www.nusl.cz/ntk/nusl-299244

- EN The muscarinic acetylcholine M2 receptor that was originally identified as the predominant muscarinic receptor subtype in the heart is also widely distributed in the central nervous system. Its signal transduction is effected by both the βγ dimer of heterotrimeric G-protein that activates potassium or inhibits calcium conductance and the αi subunit that preferentially inhibits cAMP synthesis. However, M2 muscarinic receptors expressed in CHO cells (CHO-M2) directly activate signalling pathways of all three major subclasses of G-proteins, i.e. preferred Gi/o subclass and at concentrations higher than needed for standard inhibition of forskolin-stimulated cAMP synthesis also Gs and Gq/11 subclasses to cause stimulation of cAMP synthesis and accumulation of inositolphosphates (IP), respectively . In the present experiments we investigated influence of membrane cholesterol content on activation of signalling pathways of these three G-protein subclasses in CHO-M2 cells by carbachol, a non-hydrolysable acetylcholine analogue. Treatment of cells with methyl-β-cyclodextrin decreased cell and membrane cholesterol content by 74% and 39%, respectively, and incubation in the presence of cholesterol-saturated methyl-β- cyclodextrin increased cholesterol content by 169% and 137%, respectively . Cholesterol...