A human embryonic lung fibroblast with a high density of muscarinic acetylcholine receptors.
Binding studies with the radiolabeled muscarinic antagonists dexetimide, quinuclidinyl benzilate and N-methylscopolamine showed that the human embryonic lung fibroblast CCL137 possesses approximately 2 X 10(5) muscarinic receptors/cell, i.e. 2.1 pmol/mg membrane protein. These receptors showed a marked stereoselectivity towards dexetimide and levetimide and only low affinity for another antagonist, pirenzepine. The muscarinic agonist carbamylcholine inhibited forskolin-stimulated adenylate cyclase and induced phosphatidylinositide turnover in the intact cells. Both effects were inhibited by the muscarinic antagonist atropine. Affinity labeling with tritiated propylbenzylcholine mustard revealed a protein of 72 kDa. Finally, down-regulation of the membrane receptors following prolonged treatment with the agonist carbamylcholine was assessed by means of the hydrophilic antagonist N-methylscopolamine.
André
C
C
Laboratoire de Biochimie Cellulaire, Collège de France, Paris.
Marullo
S
S
Convents
A
A
Lü
B Z
BZ
Guillet
J G
JG
Hoebeke
J
J
Strosberg
D A
DA
D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D003909:Dexetimide / Q000378:metabolism; D005347:Fibroblasts; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D008168:Lung; D019832:N-Methylscopolamine; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012602:Scopolamine Derivatives / Q000378:metabolism
D007295:Inositol Phosphates; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D003909:Dexetimide; D011813:Quinuclidinyl Benzilate; D000242:Cyclic AMP; D006152:Cyclic GMP; D019832:N-Methylscopolamine