title: 5-methoxytryptoline and close analogs as candidates for the endogenous ligand of the 3H-imipramine recognition site.
abstract: 3H-Imipramine labels with high affinity a site associated with the macromolecular complex of the serotonin transporter in brain and platelets. There is a good correlation between the potencies of drugs at inhibiting 3H-5HT uptake and at inhibiting 3H-imipramine binding. Dissociation experiments indicate that the site labelled by 3H-imipramine is not identical with the substrate recognition site of the serotonin transporter and thus, it appears that 3H-imipramine labels a modulatory site for the 5HT transport system. On this basis, the existence of an endacoid acting on the 3H-imipramine recognition site to modulate 5HT uptake is discussed. The possibility that 5-methoxytryptoline or a closely related analog may be the endogenous ligand for the 3H-imipramine recognition site is analysed on the basis of the fact that 5-methoxytryptoline is a potent inhibitor of 3H-imipramine binding that also inhibits 3H-5HT uptake.
mesh_terms: D001667:Binding, Competitive; D001792:Blood Platelets / Q000378:metabolism*; D002243:Carbolines / Q000032:analysis / Q000494:pharmacology*; D002352:Carrier Proteins; D003292:Convulsants / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007099:Imipramine / Q000378:metabolism*; D007700:Kinetics; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000097:blood / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D002243:Carbolines; D002352:Carrier Proteins; D003292:Convulsants; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter; C027775:imipramine receptor; C002272:6-methoxytryptoline; D012701:Serotonin; D007099:Imipramine