Carbachol-induced desensitization of rat basophilic leukemia (RBL-2H3) cells transfected with human m3 muscarinic acetylcholine receptors.
1. Carbachol-induced homologous desensitization of the secretory response was investigated by transfecting RBL-2H3 cells with cDNA encoding the human m3 muscarinic acetylcholine receptor (RBL-m3). 2. Exposure of RBL-m3 cells to 100 microM carbachol for 30 min in Ca2+-free medium inhibited the secretion induced by the subsequent addition of 10 microM carbachol plus Ca2+. 3. Desensitized cells bound [3H]quinuclidinyl benzilate with a similar Bmax and Kd to those of control cells. 4. The carbachol-induced transient increase in levels of inositol 1,4,5-trisphosphate was not changed by desensitization. 5. Homologous desensitization persisted when desensitized cells were permeabilized with Staphylococcal alpha-toxin.
Inoue
R
R
Department of Molecular Pharmacology, Meiji College of Pharmacy, Tokyo, Japan.
Sakurai
A
A
Tsuga
H
H
Oishi
K
K
Uchida
M K
MK
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D015471:Leukemia, Basophilic, Acute / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011813:Quinuclidinyl Benzilate; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000494:pharmacology; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D001285:Atropine; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D010738:Type C Phospholipases; D001619:beta-N-Acetylhexosaminidases; D002118:Calcium