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Pharmacological Characterization of Cholinergic Receptors in a Human Neuroblastoma Cell Line
Author(s) -
Clementi F.,
Cabrini D.,
Gotti C.,
Sher E.
Publication year - 1986
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1986.tb02861.x
Subject(s) - carbachol , pirenzepine , muscarinic acetylcholine receptor , neurotransmitter receptor , endocrinology , medicine , biology , receptor , neurotransmitter , cholinergic , biochemistry
A human neuroblastoma cell line, IMR32, has been characterized as far as morphology, membrane receptors for neurotransmitters, and uptake and release of [ 3 H]3,4‐dihydroxyphenylethylamine ([ 3 H]dopamine). These cells expressed at their surface both nicotinic and muscarinic cholinergic receptors, revealed by [ 125 I]α‐bungarotoxin and [ 3 H]quinuclidinylbenzilate ([ 3 H]QNB) binding, respectively. [ 125 I]α‐Bungarotoxin binding was efficiently inhibited by α‐bungarotoxin, nicotine, carbachol, and d ‐tubocurarine. [ 3 H]QNB binding was competitively inhibited by atropine, pirenzepine, and carbachol. Hexamethonium did not affect the binding of either ligand. In competition experiments with [ 3 H]QNB, pirenzepine recognized only one binding site with “low affinity,” and carbachol recognized two sites with different affinities, β‐adrenergic receptors were present in a very low amount, whereas α‐adrenergic and dopaminergic receptors were not detectable. IMR32 cells had an imipramine‐sensitive [ 3 H]dopamine uptake, but carbachol, high levels of K + , the calcium ionophore A23187, and α‐latrotoxin were not able to induce release of [ 3 H]dopamine that had been taken up. The ultrastructural analysis showed that IMR32 cells contained very few dense‐core vesicles, suggesting a low storage capacity for neurotransmitter. These cells could be an useful in vitro model for studying neurotransmitter receptors of the human CNS.