title: Marked reduction in the number of platelet-tritiated imipramine binding sites in geriatric depression.
abstract: The number (Bmax) and affinity (Kd) of platelet-tritiated imipramine binding sites was determined in young and middle-aged controls 50 years of age and younger (n = 25), elderly normal controls over 60 years of age (n = 18), patients who fulfilled DSM-III criteria for major depression who were under 50 years of age (n = 29), patients who fulfilled DSM-III criteria for major depression who were 60 years of age and older (n = 19), and patients who fulfilled both DSM-III criteria for primary degenerative dementia and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for probable Alzheimer's disease (n = 13). Both groups of depressed patients (under 50 and over 60 years of age) exhibited significant reductions (decreases 42%) in the number of platelet-tritiated imipramine binding sites with no change in affinity, when compared with their age-matched controls. There was little overlap in Bmax values between the elderly depressed patients and their controls. The patients with probable Alzheimer's disease showed no alteration in platelet-tritiated imipramine binding. There was no statistically significant relationship between postdexamethasone plasma cortisol concentrations and tritiated imipramine binding. These results indicate that platelet-tritiated imipramine binding may have potential utility as a diagnostic adjunct in geriatric depression, and moreover that the reduction in the number of platelet-tritiated imipramine binding sites is not due to hypercortisolemia.
authors.affiliation: Department of Psychiatry, Duke University Medical Center, Durham, NC 27710.
authors.forename: C B
authors.initials: CB
authors.lastname: Nemeroff
authors.forename: D L
authors.initials: DL
authors.lastname: Knight
authors.forename: R R
authors.initials: RR
authors.lastname: Krishnan
authors.forename: T A
authors.initials: TA
authors.lastname: Slotkin
authors.forename: G
authors.initials: G
authors.lastname: Bissette
authors.forename: M L
authors.initials: ML
authors.lastname: Melville
authors.forename: D G
authors.initials: DG
authors.lastname: Blazer
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000544:Alzheimer Disease / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D001792:Blood Platelets / Q000032:analysis / Q000378:metabolism*; D002352:Carrier Proteins; D003866:Depressive Disorder / Q000097:blood / Q000175:diagnosis / Q000378:metabolism*; D003937:Diagnosis, Differential; D006801:Humans; D007099:Imipramine / Q000378:metabolism*; D008875:Middle Aged; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter / Q000032:analysis / Q000378:metabolism*; D014316:Tritium
chemical_list: D002352:Carrier Proteins; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter; C027775:imipramine receptor; D014316:Tritium; D007099:Imipramine