In:
Journal of Neurochemistry, Wiley, Vol. 43, No. 3 ( 1984-09), p. 601-606
Abstract:
Abstract: 125 I‐Lysergic acid diethylamide ( 125 I‐LSD) is the first 125 I‐labeled ligand for serotonin receptor studies. Its binding to rat frontal cortex membranes is saturable, reversible, and stereospecific. Specific binding is linearly dependent on tissue concentration and represents 70–80% of the total binding. Scatchard plots of the binding data are linear with a K D of 1.5 n M , a B max of 12.4 fmol/mg wet weight tissue, and a Hill slope of 1.02. The binding kinetics are highly temperature‐dependent. At 37°C the bimolecular association rate constant is 1.28 × 10 8 min −1 M −1 and the dissociation rate constant is 0.087 min −1 ( t 1/2 = 8.0 min). At 0°C 〈 4% dissociation occurs over 40 min and the association rate is similarly depressed. Inhibition of 125 I‐LSD binding by a variety of serotonergic, dopaminergic, and adrenergic ligands reveals a 5‐hydroxytryptamine 2 (5‐HT 2 ) serotonergic profile for this binding site. Regional distribution studies of 125 I‐LSD binding in rat brain show that areas with the highest levels of binding include the cortex and striatum. Iodinated radioligands can be synthesized with specific activities exceeding 2,000 Ci/mmol, which makes them approximately 75‐fold more sensitive than tritiated radioligands. This high specific activity, coupled with the selectivity of 125 I‐LSD for 5‐HT 2 sites, makes this ligand a sensitive new probe for 5‐HT 2 serotonin receptors.
Type of Medium:
Online Resource
ISSN:
0022-3042
,
1471-4159
DOI:
10.1111/jnc.1984.43.issue-3
DOI:
10.1111/j.1471-4159.1984.tb12777.x
Language:
English
Publisher:
Wiley
Publication Date:
1984
detail.hit.zdb_id:
2020528-4
SSG:
12
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