title: Antidepressant-binding sites in brain and platelets.
abstract: [3H]Imipramine and [3H]paroxetine label with high affinity a site associated with the serotonin transporter in brain and platelets. The maximum binding capacity (Bmax) of [3H]imipramine in platelets is reduced in untreated depressed patients, and it may represent a useful biological marker in depression. The existence of an endogenous ligand acting on the [3H]imipramine-recognition site to modulate the serotonin transporter has been proposed by several laboratories. 5-Methoxytryptoline inhibits [3H]imipramine binding and [3H]serotonin uptake in the nanomolar range. This compound has been reported to occur in the pineal gland, but probably only in trace amounts. While the physiological relevance of 5-methoxytryptoline or a close analogue remains an open question, the possibility exists that the 'endocoid' for the [3H]imipramine-recognition site plays a role in the pathogenesis of depression.
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000378:metabolism*; D001667:Binding, Competitive; D001792:Blood Platelets / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002940:Circadian Rhythm; D003863:Depression / Q000097:blood / Q000378:metabolism; D006801:Humans; D007099:Imipramine / Q000378:metabolism; D011817:Rabbits; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D000928:Antidepressive Agents; D002352:Carrier Proteins; D011985:Receptors, Serotonin; D012701:Serotonin; D007099:Imipramine