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Background: We examined the effect of high-dose selegiline in 16 treatment-resistant older depressive patients. We hypothesized that selegiline, at a dosage of 60 mg/d, would be at least partially effective but that the higher doses would not maintain the monoamine oxidase B selectivity observed with the lower doses of selegiline., Methods: Sixteen treatment-resistant subjects (mean [+/- SD] age, 65.6 +/- 9.3 years) entered a double-blind, randomized, crossover study of placebo vs 3 weeks of selegiline at a dosage of 60 mg/d. Objective measures of mood and behavior were obtained in all subjects, and 10 of the subjects underwent repeated lumbar punctures for analysis of monoamine metabolites in the cerebrospinal fluid., Results: Objective measures of mood and behavior revealed significant improvement in the Hamilton Depression Rating Scale score (37.4% decrease), the Global Depression score (22.7% decrease), and the Brief Psychiatric Rating Scale score (19.3% decrease); subjective behavioral measures, however, did not show significant improvement during the 3-week medication trial. Cerebrospinal fluid values revealed a statistically significant drop in 3-methoxy-4-hydroxyphenylglycol (51%) and 5-hydroxyindoleacetic acid (17%) levels, and there was a significant lowering of systolic blood pressure on standing (15%), but these changes were not accompanied by clinical side effects., Conclusions: Our results suggest that high-dose selegiline can be an effective antidepressant in treatment-resistant older depressive patients. While the selegiline dose required has nonselective monoamine oxidase effects and thus would not be free of possible tyramine interactions, other advantages suggest that further investigations with selegiline are warranted in this population.

A high-affinity muscarinic receptor antagonist, 123IQNB (3-quinuclidinyl-4-iodobenzilate labeled with iodine 123), was used with single photon emission computed tomography to image muscarinic acetylcholine receptors in 14 patients with dementia and in 11 healthy controls. High-resolution single photon emission computed tomographic scanning was performed 21 hours after the intravenous administration of approximately 5 mCi of IQNB. In normal subjects, the images of retained ligand showed a consistent regional pattern that correlated with postmortem studies of the relative distribution of muscarinic receptors in the normal human brain, having high radioactivity counts in the basal ganglia, occipital cortex, and insular cortex, low counts in the thalamus, and virtually no counts in the cerebellum. Eight of 12 patients with a clinical diagnosis of Alzheimer's disease had obvious focal cortical defects in either frontal or posterior temporal cortex. Both patients with a clinical diagnosis of Pick's disease had obvious frontal and anterior temporal defects. A region of interest statistical analysis of relative regional activity revealed a significant reduction bilaterally in the posterior temporal cortex of the patients with Alzheimer's disease compared with controls. This study demonstrates the practicability of acetylcholine receptor imaging with 123IQNB and single photon emission computed tomography. The data suggest that focal abnormalities in muscarinic binding in vivo may characterize some patients with Alzheimer's disease and Pick's disease, but further studies are needed to address questions about partial volume artifacts and receptor quantification.

The serotonin agonist m-chlorophenylpiperazine (mCPP) was administered intravenously to 12 patients with Alzheimer's disease and ten age-matched controls. It produced distinct behavioral effects in both treatment groups; however, significantly greater responsivity to mCPP was found in patients with Alzheimer's disease than in controls in measures of psychomotor activation, restlessness, and perceptual abnormalities. Significant and similar increases in plasma prolactin and cortisol levels were found in both patients with Alzheimer's disease and controls following the administration of mCPP vs placebo. Furthermore, blood pressure and pulse changes following mCPP were not significantly different between the groups. Elderly controls, however, did show a significantly greater temperature response following mCPP than did patients with Alzheimer's disease. The overall cognitive effects of mCPP were minimal; however, mCPP produced significantly greater worsening in recent memory and knowledge memory in patients with Alzheimer's disease than in controls. These findings could not be explained by pharmacokinetic differences across populations, because plasma concentrations of mCPP were similar in patients with Alzheimer's disease and controls. The increased behavioral responsivity but unchanged neuroendocrine or other physiologic responsivity to mCPP may be related to damaged brain serotonin neurons or other neuronal systems that interact with serotonin neurons that have been found in postmortem and biopsy studies of patients with Alzheimer's disease.