( sup 3 H)cytisine binding to nicotinic cholinergic receptors in brain

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Molecular Pharmacology; (USA)

OSTI ID:5988845

Pabreza, L A; Dhawan, S; Kellar, K J ^[1]

---

1. Georgetown Univ. School of Medicine, Washington, DC (USA)

Cytisine, a ganglionic agonist, competes with high affinity for brain nicotinic cholinergic receptors labeled by any of several nicotinic {sup 3}H-agonist ligands. Here we have examined the binding of ({sup 3}H)cytisine in rat brain homogenates. ({sup 3}H)Cytisine binds with high affinity (Kd less than 1 nM), and specific binding represented 60-90% of total binding at all concentrations examined up to 15 nM. The nicotinic cholinergic agonists nicotine, acetylcholine, and carbachol compete with high affinity for ({sup 3}H)cytisine binding sites, whereas among nicotinic receptor antagonists only dihydro-beta-erythroidine competes with high affinity (in the nanomolar range). Comparison of binding in several brain regions showed that ({sup 3}H)cytisine binding is higher in the thalamus, striatum, and cortex than in the hippocampus, cerebellum, or hypothalamus. The pharmacology and brain regional distribution of ({sup 3}H)cytisine binding sites are those predicted for neuronal nicotinic receptor agonist recognition sites. The high affinity and low nonspecific binding of ({sup 3}H)cytisine should make it a very useful ligand for studying neuronal nicotinic receptors.

• OSTI ID: 5988845
• Journal Information: Molecular Pharmacology; (USA), Journal Name: Molecular Pharmacology; (USA) Vol. 39:1; ISSN MOPMA; ISSN 0026-895X
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
AFFINITY
AMINES
AMMONIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
CPB
DISTRIBUTION
DRUGS
ESTERS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LIGANDS
MAMMALS
MEMBRANE PROTEINS
NERVE CELLS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOMIMETICS
PROTEINS
QUATERNARY COMPOUNDS
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SOMATIC CELLS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES