These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.
Pubmed for Handhelds
PUBMED FOR HANDHELDS
Search MEDLINE/PubMed
Title: Coupling of transfected muscarinic acetylcholine receptor subtypes to phospholipase D. Author: Sandmann J, Peralta EG, Wurtman RJ. Journal: J Biol Chem; 1991 Apr 05; 266(10):6031-4. PubMed ID: 2007563. Abstract: Muscarinic receptor-induced changes in the activities of phospholipase D (PLD) and of phosphoinositide-phospholipase C (PI-PLC) were investigated in human embryonic kidney (HEK) cells transfected with, and stably expressing, the human m1, m2, m3, and m4 mAChR subtypes, respectively. PLD and PI-PLC activities in these four transfected cell lines as well as in nontransfected cells were measured by the formation of [3H]phosphatidylethanol [( 3H]PEt) and [3H]inositol phosphates [( 3H]IP) after labeling cellular phospholipids with [3H]oleic acid and [3H]inositol. The muscarinic receptor agonist carbachol had no significant effects on [3H]PEt and [3H]IP formation in nontransfected HEK cells. In cells expressing the m1 or m3 receptors carbachol (1 mM; in the presence of 400 mM ethanol and 10 mM lithium chloride) caused the formation of [3H]PEt of about 12,000 cpm/mg protein (basal PEt formation was not measurable) and increased [3H]IP formation by 20,000-30,000 cpm/mg (a 7-10-fold increase over basal levels). The EC50 values (0.3-1.5 microM) were similar for both effects and both mAChR subtypes. In contrast, in cells expressing m2 or m4 receptor subtypes the magnitude of [3H]PEt (about 4,000 cpm/mg protein) or [3H]IP (3,000-4,000 cpm/mg) formation was much smaller and the EC50 values (20-40 microM) much higher than for the m1 and m3 receptors. Neomycin (1 mM) inhibited the m1 and m3 receptor-mediated production of IP by 50%, whereas the PEt formation was attenuated by 20% in the same cells. We conclude that activation of all of the four mAChR subtypes, although with different efficiencies, can stimulate PLD. The m1 and m3 receptor-mediated stimulation of the PLD may be at least partially independent of the PI-PLC stimulation.[Abstract] [Full Text] [Related] [New Search]