Studies on the characterization and regulation of alpha-1 adrenergic receptors and (/sup 3/H)WB4101 binding sites in the central nervous system

Book · Tue Jan 01 00:00:00 EST 1985

OSTI ID:6025912

Morrow, A L

The purpose of these studies has been to resolve the anomalous binding characteristics of two alpha adrenergic receptor ligands, (/sup 3/H)WB4101 and (/sup 3/H)prazosin and to study the regulation of the receptors labeled by these compounds after surgical denervation and chronic drug treatments. Preliminary studies indicated that (/sup 3/H)WB4101 binding sites, which were believed to represent alpha-1 adrenergic receptors, were increased in number following removal of the fimbrial afferents to the hippocampus. This increase was not due to removal of the adrenergic input into this structure since destruction of the locus coeruleus or the dorsal noradrenergic bundle did not produce the up-regulation. Characterization of alpha-1 adrenergic receptors using (/sup 3/H)prazosin and (/sup 3/H)WB4101 revealed evidence for subtypes of alpha-1 receptors designated alpha-1A and alpha-1B. The nanomolar affinity component of (/sup 3/H)WB4101 binding is not adrenergic but serotonergic. The serotonergic agonists, serotonin and 8-hydroxy-dipropylaminotetraline have affinities of 1.5 and 3.0 nM for this site, when studied in the presence of a 30 nM prazosin mask of the alpha-1 component of (/sup 3/H)WB4101 binding. Fimbria transection or 5,7 dihydroxytryptamine injections produced increases in the Bmax of the nanomolar affinity component of (/sup 3/H)WB4101 binding in the presence of a prazosin mask. The up-regulated site showed identical serotonergic pharmacology compared to control tissue. Thus, the author concluded that serotonergic denervation of the hippocampus produces the increase in serotonergic binding sites labeled by (/sup 3/H)WB4101.

• Research Organization: California Univ., San Diego (USA)
• OSTI ID: 6025912
• Resource Relation: Other Information: Thesis
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
RECEPTORS
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SEROTONIN
SYMPATHOMIMETICS
AFFINITY
BIOCHEMICAL REACTION KINETICS
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CENTRAL NERVOUS SYSTEM
LIGANDS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINES
AROMATICS
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AZOLES
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ISOTOPE APPLICATIONS
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NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PROTEINS
PYRROLES
RADIOPROTECTIVE SUBSTANCES
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550201* - Biochemistry- Tracer Techniques