title: Characteristics of high affinity binding of [3H]N-acetylserotonin in rat brain.
abstract: Evidence that the putative pineal hormone, N-acetylserotonin (NAS), is present in diverse areas of the brain of the rat and that this compound is biologically active, prompted a study of its central binding characteristics. [3H]N-acetylserotonin [( 3H]-NAS) exhibits specific, saturable and high affinity binding in synaptosomal fractions from the brain of the rat. In fresh CNS membranes, [3H]N-acetylserotonin appeared to bind to a single population of high affinity sites with a dissociation constant (Kd) of 3-5 nM and a maximal binding site concentration (Bmax) of 250-400 fmol mg-1 protein. A comparison of the regional distribution of the binding of [3H]N-acetylserotonin and [3H]-5-hydroxytryptamine [( 3H]-5-HT) indicated that both radioligands exhibited the greatest binding in the striatum and frontal cortex, while relatively more [3H]N-acetylserotonin was bound in the cerebellum and brainstem. The structural specificity of the binding suggests that [3H]N-acetylserotonin labelled serotonergic receptors in the frontal cortex.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000031:analogs & derivatives* / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism
chemical_list: D012701:Serotonin; C006389:N-acetylserotonin