Wegener S, Spindler-Barth M, Spindler KD. A muscarinic acetylcholine receptor, present in the epithelial cell line from Chironomus tentans.
Biol Chem 1996;
377:819-24. [PMID:
8997492 DOI:
10.1515/bchm3.1996.377.12.819]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A muscarinic cholinergic receptor (mAchR) is present in the non-neuronal epithelial cell line from Chironomus tentans. Scatchard plot analysis (KD = 1.4 nM) using the non-selective antagonist quinuclidinylbenzilate (QNB), as well as kinetic data (KD = 1.7 nM), reveals one class of high affinity binding sites. About 2000 binding sites/cell are present. The receptor concentration (54.5 +/- 7.5 fmol/mg protein) is comparable to the values reported from insect brain. The receptor interacts only with muscarinic ligands; nicotinergic acetylcholine receptors are not present. Binding properties are not comparable to any of the muscarinic subtypes known from vertebrate tissues. The rank order of competition of radiolabelled QNB is: QNB > atropine > PrBCM > oxotremorine, pirenzepine > methoctramine. The competition curve obtained with carbamylcholine is shifted to higher ligand concentrations in the presence of Gpp(NH)p and to lower carbamylcholine concentrations by 1 mM NEM. With antibodies against muscarinic receptor from calf brain one band with a molecular weight of about 80 kDa is detected on Western blots. The moulting hormone 20-OH-ecdysone transiently increases the concentration of muscarinic receptor.
Collapse