RT Journal Article SR Electronic T1 Novel receptor site involved in enhancement of stimulus-induced acetylcholine, dopamine, and serotonin release. JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 16 OP 21 VO 40 IS 1 A1 S W Tam A1 D Rominger A1 V J Nickolson YR 1991 UL http://molpharm.aspetjournals.org/content/40/1/16.abstract AB The cognitive enhancer DuP 996 [3,3-bis(4-pyrindinylmethyl)-1-phenylindolin-2-one] and its structural analogs enhance the K(+)-stimulated release of acetylcholine, dopamine, and serotonin in brain slices, without effect on basal release. A novel receptor site labeled by [3H]DuP 996 has been identified. The [3H]DuP 996 binding site has a Kd of 19 nM and a Bmax of 102 fmol/mg of protein. Binding to this site is specific, saturable, reversible, and time, pH, and temperature dependent. Specific binding is decreased by treatment with trypsin and not affected by phospholipase C. Specific binding is inhibited by Ca2+ and increased by Mn2+ but not affected by Na+, K+, or Mg2+. The [3H]DuP 996 binding sites are heterogeneously distributed in brain, with striatum and hypothalamus having highest density and cerebellum lowest. The [3H]DuP 996 binding site does not belong to any known class of receptor site, because [3H]DuP 996 binding could not be displaced by a broad variety of standard pharmacological agents and neuropeptides. Physiological significance of this binding site is suggested by the excellent correlation between the binding affinity for this site and the potency to enhance K(+)-stimulated release of acetylcholine for a series of DuP 996 analogs. Ligands for this receptor site may have therapeutic potential for the treatment of cognitive deficits and neurodegenerative diseases.