TY - JOUR
T1 - Stereoselective L-[3H]quinuclidinyl benzilate-binding sites in nervous tissue of Aplysia californica
T2 - Evidence for muscarinic receptors
AU - Murray, T. F.
AU - Mpitsos, G.
AU - Siebenaller, J. F.
AU - Barkers, D. L.
PY - 1985
Y1 - 1985
N2 - The muscarinic antagonist L-[3H]quinuclidinyl benzilate (L-[3H]QNB) binds with a high affinity (K(d) = 0.77 nm) to a single population of specific sites (B(max) = 47 fmol/mg of protein) in nervous tissue of the gastropod mullusc, Aplysia. The specific L-[3H]QNB binding is displaced stereoselectively by the enantiomers of benzetimide, dexetimide,and levetimide. The pharmacologically active enantiomer, dexetimide, is more potent than levetimide as an inhibitor of L-[3H]QNB binding. Moreover, the muscarinic cholinergic ligands, scopolamine, atropine, oxotremorine, and pilocarpine are effective inhibitors of the specific L-[3H]QNB binding, whereas nicotinic receptor antagonists, decamethonium and d-tubocurarine, are considerably less effective. These pharmacological characteristics of the L-[3H]QNB-binding site provide evidence for classical muscarinic receptors in Aplysia nervous tissue. The physiological relevance of the dexetimide-displaceable L-[3H]QNB-binding site was supported by the demonstration of the sensitivity of the specific binding to thermal denaturation. Specific binding of L-[3H]QNB was also detected in nervous tissue of another marine gastropod, Pleurobranchaea californica. The characteristics of the Aplysia L-[3H]QNB-binding site are in accordance with studies of numerous vertebrate and invertebrate tissues indicating that the muscarinic cholinergic receptor site has been highly conserved through evolution.
AB - The muscarinic antagonist L-[3H]quinuclidinyl benzilate (L-[3H]QNB) binds with a high affinity (K(d) = 0.77 nm) to a single population of specific sites (B(max) = 47 fmol/mg of protein) in nervous tissue of the gastropod mullusc, Aplysia. The specific L-[3H]QNB binding is displaced stereoselectively by the enantiomers of benzetimide, dexetimide,and levetimide. The pharmacologically active enantiomer, dexetimide, is more potent than levetimide as an inhibitor of L-[3H]QNB binding. Moreover, the muscarinic cholinergic ligands, scopolamine, atropine, oxotremorine, and pilocarpine are effective inhibitors of the specific L-[3H]QNB binding, whereas nicotinic receptor antagonists, decamethonium and d-tubocurarine, are considerably less effective. These pharmacological characteristics of the L-[3H]QNB-binding site provide evidence for classical muscarinic receptors in Aplysia nervous tissue. The physiological relevance of the dexetimide-displaceable L-[3H]QNB-binding site was supported by the demonstration of the sensitivity of the specific binding to thermal denaturation. Specific binding of L-[3H]QNB was also detected in nervous tissue of another marine gastropod, Pleurobranchaea californica. The characteristics of the Aplysia L-[3H]QNB-binding site are in accordance with studies of numerous vertebrate and invertebrate tissues indicating that the muscarinic cholinergic receptor site has been highly conserved through evolution.
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U2 - 10.1523/jneurosci.05-12-03184.1985
DO - 10.1523/jneurosci.05-12-03184.1985
M3 - Article
C2 - 4078624
AN - SCOPUS:0022271893
VL - 5
SP - 3184
EP - 3188
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 12
ER -