Binding sites with high affinity and specificity for [3H]quinuclidinyl benzilate (QNB) are present in homogenates of rat brain. The characteristics of the binding sites resemble those of muscarinic cholinergic receptors. Specific binding is saturable with respect to [3H]QNB and tissue concentration and is time, temperature, and pH dependent. The bimolecular rate of association (2.0 x 108 M-1 min-1) and dissociation (1.2 x 10-2 min-1) at 35°C indicate a dissociation constant of 60 pM and a density of 65 pmol/g of brain. Muscarinic antagonists and agonists displace specific [3H]QNB binding, while nicotinic and noncholinergic drugs possess little affinity for [3H]QNB binding sites.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1974|
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