Stereoselective L-(3H)quinuclidinyl benzilate-binding sites in nervous tissue of Aplysia californica: evidence for muscarinic receptors

Journal Article · Sun Dec 01 04:00:00 EST 1985 · J. Neurosci.; (United States)

OSTI ID:5810956

Murray, T F; Mpitsos, G J; Siebenaller, J F; Barker, D L

The muscarinic antagonist L-(/sup 3/H)quinuclidinyl benzilate (L-(/sup 3/H)QNB) binds with a high affinity (Kd = 0.77 nM) to a single population of specific sites (Bmax = 47 fmol/mg of protein) in nervous tissue of the gastropod mollusc, Aplysia. The specific L-(/sup 3/H)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-(/sup 3/H)QNB binding. Moreover, the muscarinic cholinergic ligands, scopolamine, atropine, oxotremorine, and pilocarpine are effective inhibitors of the specific L-(/sup 3/H)QNB binding, whereas nicotinic receptor antagonists, decamethonium and d-tubocurarine, are considerably less effective. These pharmacological characteristics of the L-(/sup 3/H)QNB-binding site provide evidence for classical muscarinic receptors in Aplysia nervous tissue. The physiological relevance of the dexetimide-displaceable L-(/sup 3/H)QNB-binding site was supported by the demonstration of the sensitivity of the specific binding to thermal denaturation. Specific binding of L-(/sup 3/H)QNB was also detected in nervous tissue of another marine gastropod, Pleurobranchaea californica. The characteristics of the Aplysia L-(/sup 3/H)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.

• Research Organization: Oregon State Univ., Newport
• OSTI ID: 5810956
• Journal Information: J. Neurosci.; (United States), Journal Name: J. Neurosci.; (United States) Vol. 12; ISSN JNRSD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
AQUATIC ORGANISMS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BENZILIC ACID
BODY
CARBOXYLIC ACIDS
DRUGS
HYDROXY ACIDS
INHIBITION
INVERTEBRATES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MEMBRANE PROTEINS
MOLLUSCS
NERVE TISSUE
ORGANIC ACIDS
ORGANIC COMPOUNDS
PARASYMPATHOLYTICS
PROTEINS
RECEPTORS
TISSUES
TRACER TECHNIQUES
TRITIUM COMPOUNDS