Biomedical subjects

Alan F Schatzberg

Publications and source records attributed to Alan F Schatzberg.

At least 19 recordsLinked to original sources

PubMed2007

Resting-state functional connectivity in major depression: abnormally increased contributions from subgenual cingulate cortex and thalamus.

BACKGROUND: Positron emission tomography (PET) studies of major depression have revealed resting-state abnormalities in the prefrontal and cingulate cortices. Recently, fMRI has been adapted to examine connectivity within a specific resting-state neural network--the default-mode network--that includes medial prefrontal and anterior cingulate cortices. The goal of this study was to examine resting-state, default-mode network functional connectivity in subjects with major depression and in healthy controls. METHODS: Twenty-eight subjects with major depression and 20 healthy controls underwent 5-min fMRI scans while resting quietly. Independent component analysis was used to isolate the default-mode network in each subject. Group maps of the default-mode network were compared. A within-group analysis was performed in the depressed group to explore effects of depression refractoriness on functional connectivity. RESULTS: Resting-state subgenual cingulate and thalamic functional connectivity with the default-mode network were significantly greater in the depressed subjects. Within the depressed group, the length of the current depressive episode correlated positively with functional connectivity in the subgenual cingulate. CONCLUSIONS: This is the first study to explore default-mode functional connectivity in major depression. The findings provide cross-modality confirmation of PET studies demonstrating increased thalamic and subgenual cingulate activity in major depression. Further, the within-subject connectivity analysis employed here brings these previously isolated regions of hypermetabolism into the context of a disordered neural network. The correlation between refractoriness and subgenual cingulate functional connectivity within the network suggests that a quantitative, resting-state fMRI measure could be used to guide therapy in individual subjects.

Adult↗

PubMed2006

Social stress-related behavior affects hippocampal cell proliferation in mice.

Although social stress inhibits neurogenesis in the adult hippocampus, the extent to which individual differences in stress-related behavior affect hippocampal cell proliferation is not well understood. Based on results from resident-intruder stress tests administered to adult male mice, here we report that individual differences in hippocampal cell proliferation are related to the frequency of defensive behavior, and not the amount of aggression received or the frequency of fleeing. In contrast, access to voluntary wheel-running exercise did not affect hippocampal cell proliferation in either stressed or non-stressed mice. Social stress-induced inhibition of cell proliferation was restricted to the hippocampus, as neither stress nor access to wheel-running exercise altered cell proliferation in the amygdala. These findings indicate that individual differences in stress-related behavior influence cell proliferation in the mouse hippocampus, and may have important implications for understanding structural and functional hippocampal impairments in human psychiatric patients.

Aggression↗

PubMed2006

Report by the ACNP Task Force on response and remission in major depressive disorder.

This report summarizes recommendations from the ACNP Task Force on the conceptualization of remission and its implications for defining recovery, relapse, recurrence, and response for clinical investigators and practicing clinicians. Given the strong implications of remission for better function and a better prognosis, remission is a valid, clinically relevant end point for both practitioners and investigators. Not all depressed patients, however, will reach remission. Response is a less desirable primary outcome in trials because it depends highly on the initial (often single) baseline measure of symptom severity. It is recommended that remission be ascribed after 3 consecutive weeks during which minimal symptom status (absence of both sadness and reduced interest/pleasure along with the presence of fewer than three of the remaining seven DSM-IV-TR diagnostic criterion symptoms) is maintained. Once achieved, remission can only be lost if followed by a relapse. Recovery is ascribed after at least 4 months following the onset of remission, during which a relapse has not occurred. Recovery, once achieved, can only be lost if followed by a recurrence. Day-to-day functioning and quality of life are important secondary end points, but they were not included in the proposed definitions of response, remission, recovery, relapse, or recurrence. These recommendations suggest that symptom ratings that measure all nine criterion symptom domains to define a major depressive episode are preferred as they provide a more certain ascertainment of remission. These recommendations were based largely on logic, the need for internal consistency, and clinical experience owing to the lack of empirical evidence to test these concepts. Research to evaluate these recommendations empirically is needed.

Clinical Trials as Topic↗

PubMed2006

The neuropsychological profile of psychotic major depression and its relation to cortisol.

BACKGROUND: Our study described the neuropsychological profile of psychotic major depression (PMD) compared to nonpsychotic major depression (NPMD) patients and psychiatrically healthy controls (HC). We predicted that higher cortisol levels would be associated with greater cognitive deficits. METHODS: Twenty-nine PMDs, 24 NPMDs, and 26 HCs were recruited at Stanford University Medical Center. Psychiatric ratings, cortisol levels from 1800-0900 hours, and neuropsychological test data were obtained. RESULTS: PMDs had more severe cognitive impairments compared with NPMDs and HCs with the exception of simple verbal attention. PMDs had elevated mean cortisol levels from 1800 to 0100 hours which were significantly correlated with poorer verbal memory and psychomotor speed performance. Cortisol slopes from 1800 to 0100 hours were also significantly correlated with verbal memory and working memory. CONCLUSIONS: While PMDs' ability to attend passively to information appears intact, they have more difficulty processing, manipulating, and encoding new information. Elevated cortisol levels, as seen in PMD patients, are associated with poorer cognitive performance especially related to verbal memory for lists of words and working memory.

Adrenocorticotropic Hormone↗

PubMed2006

Maternal mediation, stress inoculation, and the development of neuroendocrine stress resistance in primates.

The stress inoculation hypothesis presupposes that brief intermittent stress exposure early in life induces the development of subsequent stress resistance in human and nonhuman primates. Rodent studies, however, suggest a role for maternal care rather than stress exposure per se (i.e., the maternal mediation hypothesis). To investigate these two hypotheses, we examined maternal care and the development of stress resistance after exposure to brief intermittent infant stress (IS), mother-infant stress (MIS), or no stress (NS) protocols administered to 30 monkeys between postnatal weeks 17 and 27. Unlike rodents, the IS condition did not permanently increase primate maternal care, nor did measures of total maternal care predict subsequent offspring hypothalamic-pituitary-adrenal-axis responsivity. Although MIS infants received less maternal care than IS and NS infants, both IS and MIS monkeys developed subsequent stress resistance. These findings indicate that rearing differences in the development of stress resistance are more closely related to differences in prior stress exposure than to differences in maternal care. A second experiment confirmed this conclusion in a different cohort of 25 monkeys exposed as infants to high foraging-demand (HFD) or low foraging-demand (LFD) conditions. HFD infants exhibited intermittent elevations in cortisol levels and received less maternal care than LFD infants. In keeping with a key prediction of the stress inoculation hypothesis, HFD males responded to stress in adulthood with diminished hypothalamic-pituitary-adrenal-axis activation compared with LFD males. Results from both experiments demonstrate that stress inoculation, rather than high levels of maternal care, promotes the development of primate stress resistance.

Adrenocorticotropic Hormone↗

PubMed2006

Cortisol circadian rhythm alterations in psychotic major depression.

BACKGROUND: Increased hypothalamic-pituitary-adrenal axis activity is well described in psychotic depression with an emphasis on 24-hour, urinary free cortisol levels or dexamethasone suppression tests. There are limited data on cortisol levels during specific times of the day. METHODS: Patients with depression with (PMD) and without (NPMD) psychosis and healthy control subjects were studied using rating scales of depression and psychosis and measures of HPA activity, including overnight cortisol and adrenocorticotropin levels. We used analysis of variance to determine group differences and regression analyses to assess contributions of specific measures to cortisol levels. RESULTS: PMDs had higher cortisol during the evening hours than did NPMDs or control subjects, who did not differ from one another. Regression analyses suggest that depression and the combination of depressive and psychotic symptoms were important contributors to variance in evening cortisol. CONCLUSIONS: PMD is associated with increased cortisol levels during the quiescent hours. Enhanced cortisol activity, particularly a higher nadir, was related to depression severity and the interaction of depressive and psychotic symptoms. This increase suggests a defect in the action of the circadian timing system and HPA axis, creating a hormonal milieu similarly seen in early Cushing's syndrome and potentially an (im)balance of mineralocorticoid and glucocorticoid receptor activity.

Adrenocorticotropic Hormone↗

PubMed2006

Application of microarray technology in primate behavioral neuroscience research.

Gene expression profiling of brain tissue samples applied to DNA microarrays promises to provide novel insights into the neurobiological bases of primate behavior. The strength of the microarray technology lies in the ability to simultaneously measure the expression levels of all genes in defined brain regions that are known to mediate behavior. The application of microarrays presents, however, various limitations and challenges for primate neuroscience research. Low RNA abundance, modest changes in gene expression, heterogeneous distribution of mRNA among cell subpopulations, and individual differences in behavior all mandate great care in the collection, processing, and analysis of brain tissue. A unique problem for nonhuman primate research is the limited availability of species-specific arrays. Arrays designed for humans are often used, but expression level differences are inevitably confounded by gene sequence differences in all cross-species array applications. Tools to deal with this problem are currently being developed. Here we review these methodological issues, and provide examples from our experiences using human arrays to examine brain tissue samples from squirrel monkeys. Until species-specific microarrays become more widely available, great caution must be taken in the assessment and interpretation of microarray data from nonhuman primates. Nevertheless, the application of human microarrays in nonhuman primate neuroscience research recovers useful information from thousands of genes, and represents an important new strategy for understanding the molecular complexity of behavior and mental health.

Animals↗

PubMed2006

New paradigm for treating recurrent depression: from symptom control to managing enduring vulnerabilities.

Optimal management of depression remains a long-term challenge. Long-term maintenance treatment with antidepressants has been shown to be effective for preventing or delaying recurrence for many patients with a history of previous multiple episodes. However, aside from a history of multiple recurrences, it remains difficult to identify patients who are most likely to experience recurrence and when. Thus we do not really know who might particularly benefit from maintenance therapy and what type may be efficacious. In patients with depression, research has shown there are structural and functional alterations in the brain, particularly in patients with recurrent or chronic depression. These changes have been generally viewed to be consequences of the disease, which are seen to worsen with a longer duration of untreated illness and with a greater number of depressive episodes. However, these neurobiological characteristics may also represent risk factors or vulnerabilities that predispose some patients to chronic or recurrent depression. Additional research has demonstrated that antidepressant treatment may reduce or modulate these functional and structural changes, suggesting that long-term treatment may, in fact, benefit patients not only by controlling symptoms but also by managing these underlying vulnerabilities. A new treatment paradigm, which focuses on identifying patients with risk factors and managing the disease process rather than suppression of symptoms, is needed for recurrent depression.

Major Depressive Disorder↗

PubMed2006

Extended treatment with bupropion SR for cigarette smoking cessation.

The authors present results of a randomized clinical trial of the efficacy of extended treatment with bupropion SR in producing longer term cigarette smoking cessation. Adult smokers (N = 362) received open-label treatment (11 weeks) that combined relapse prevention training, bupropion SR, and nicotine patch followed by extended treatment (14 weeks) with bupropion SR or matching placebo. Abstinence percentages were relatively high (week 11: 52%; week 25: bupropion, 42%; placebo, 38%; week 52: bupropion, 33%; placebo, 34%), but bupropion SR did not surpass placebo. Gender and baseline craving level were identified as significant, independent moderators of treatment response. Men were more likely to abstain than women (week 11: 59% vs. 43%, p = .001; week 25: 48% vs. 31%, p = .001; week 52: 39% vs. 27%, p = .01). Because most smokers suffer relapse with any current cessation treatment, the comparatively high abstinence percentages achieved in this trial are of interest.

Adolescent↗

PubMed2006

Clinical and biological effects of mifepristone treatment for psychotic depression.

Psychotic major depression (PMD) is found to be a relatively common psychiatric condition that affects up to nearly 20% of patients with major depression. Previous studies by our group have shown rapid reversal of psychotic symptoms in some PMD patients treated with mifepristone, in addition to restoring a more normal afternoon cortisol release. The rationale for treating patients with PMD with a glucocorticosteroid receptor antagonist is further discussed. In total, 30 patients with PMD were treated with either 600 mg/day mifepristone or placebo for 8 days in a randomized double-blind manner. The Hamilton Depression Rating Scale (HDRS) and the Brief Psychiatric Rating Scale (BPRS) were administered at baseline and again after 8 days of treatment. Cortisol and ACTH were measured hourly from 1800 to 0900 at baseline and after 8 days of treatment. Significantly, more patients in the mifepristone group (seven of 15) showed a 50% or greater decline on the BPRS positive symptom subscale, an index of psychotic symptoms, as compared to the placebo group (two of 15). Patients who received mifepristone had lower HDRS and BPRS scores at study completion compared to those who received placebo, but these differences were not statistically significant. In addition, mifepristone significantly elevated cortisol and ACTH levels and steepened ascending slopes from 1800 to 0100 and from 0100 to 0900 as compared to placebo. Clinical and biological effects of mifepristone were comparable among males and females. Age was found to significantly and positively correlate with changes in cortisol and ACTH. These results suggest that short-term use of mifepristone may be effective in the treatment of PMD and may re-regulate the HPA axis. Additional blinded studies are warranted.

Adrenocorticotropic Hormone↗

PubMed2006

Antidepressant discontinuation syndrome: consensus panel recommendations for clinical management and additional research.

OBJECTIVE: Currently, no evidence-based guidelines exist for the management of serotonin reuptake inhibitor (SRI) discontinuation syndrome. This article summarizes recommendations with respect to future research as well as clinical management recommendations for SRI discontinuation syndrome. PARTICIPANTS: In April 2004, a panel of physicians convened in New York City to discuss recommendations for clinical management of and additional research on SRI discontinuation syndrome. EVIDENCE: Previous guidance for management of SRI discontinuation syndrome was proposed in 1997 in a consensus meeting also chaired by Alan F. Schatzberg. A literature search of the PubMed database was conducted to identify articles on SRI discontinuation syndrome that have been published since 1997. CONSENSUS PROCESS: The 2004 panel reviewed important preclinical and clinical studies, discussed prospective investigation of this syndrome in clinical trials, and suggested the establishment of a research network to collect data in naturalistic settings. The panel also reviewed the management recommendations published in 1997 and subsequently updated the recommendations, taking into account the latest clinical data as well as the personal experience of its members with patients. CONCLUSIONS: Additional preclinical and clinical studies are necessary to further elucidate the underlying biological mechanisms of SRI discontinuation syndrome and to identify the patient populations and agents that are most affected by this phenomenon. Management strategies include gradual tapering of doses and should emphasize clinical monitoring and patient education.

Antidepressive Agents↗

PubMed2005

Detecting psychotic major depression using psychiatric rating scales.

OBJECTIVE: The aim of this study was to assess whether individual or clusters of psychiatric symptoms can differentiate patients with psychotic major depression (PMD) from those with nonpsychotic depression (NPMD). METHOD: Data were pooled from two studies investigating patients with moderate depression. A total of 129 subjects were studied. Patients in Sample 1 were unmedicated, while the majority of the patients in Sample 2 were taking psychotropic medications. Baseline rating scales were obtained for all subjects, including the Hamilton depression rating scale and the brief psychiatric rating scale (BPRS). We used discriminant function analyses, logistic regression, and ROC analyses to determine the patterns in symptoms that differentiated the groups. RESULTS: Psychotic patients were adequately differentiated by the unusual thought content (UTC) item of the BPRS. Even mild UTC endorsement was an indicator of PMD. Furthermore, results suggest that the positive symptom subscale of the BPRS was even better at differentiating PMD from NMPD patients. Sensitivity and specificity for this scale were 84% and 99%, respectively. CONCLUSION: Psychotic major depression is often undiagnosed and poorly treated. One reason for this trend is the failure of physicians to inquire in a more detailed manner about positive symptoms in patients with primary mood symptoms. Although physicians are not likely to have the time to conduct an entire BPRS during an evaluation, our results suggest that a few key symptoms, if assessed directly, may aid the psychiatrist to more effectively diagnose and subsequently treat their depressed patients.

Adult↗

PubMed2005

Mild early life stress enhances prefrontal-dependent response inhibition in monkeys.

BACKGROUND: Severely stressful early experiences have been implicated in the pathophysiology of psychiatric disorders. In contrast, exposure to mild early life stress (i.e., stress inoculation) strengthens emotional and neuroendocrine resistance to subsequent stressors. Herein we extend this research to examine the effects of mild early life stress on cognition. METHODS: Squirrel monkeys were randomized to a mild intermittent stress (IS; n = 11) or nonstress (NS; n = 9) condition from 17 to 27 weeks postpartum. At 1.5 years of age, monkeys were assessed for response inhibition on a test previously shown to reflect prefrontal-dependent cognitive function. RESULTS: IS monkeys demonstrated fewer response inhibition errors compared with NS monkeys. There were no rearing-related differences in aspects of performance that did not require inhibitory control. Compared with NS monkeys, IS monkeys had lower basal plasma pituitary-adrenal stress hormone levels. No rearing-related differences on neuroendocrine measures obtained 15 minutes after testing were found. CONCLUSIONS: Results from this experiment provide the first evidence that exposure to mildly stressful early experiences improves prefrontal-dependent response inhibition in primates. Combined with our previous data, findings from this animal model suggest that exposure to mild early life stress may enhance the development of brain systems that regulate emotional, neuroendocrine, and cognitive control.

Adrenal Cortex Hormones↗

PubMed2005

Mutations in squirrel monkey glucocorticoid receptor impair nuclear translocation.

To identify the determinants of impaired glucocorticoid receptor (GR) signaling in a model of glucocorticoid resistance, cloned GR from Guyanese squirrel monkeys (gsmGR) was tagged with enhanced green fluorescent protein, and nuclear translocation was examined in transfected COS1 cells. In keeping with evidence that gsmGR transactivational competence is impaired, we found that nuclear translocation is likewise diminished in gsmGR relative to human GR (hGR). Experiments with GR chimeras revealed that replacement of the gsmGR ligand binding domain (LBD) with that from hGR increased translocation. Truncated gsmGR constructs lacking the LDB after amino acid 552 also showed increased translocation even in the absence of cortisol. Three back-mutations of gsmGR to hGR (Thr551Ser, Ala616Ser, and Ser618Ala) in the LBD confirmed that these amino acids play a role in diminished translocation.

Animals↗

PubMed2005

On the interactions of the hypothalamic-pituitary-adrenal (HPA) axis and sleep: normal HPA axis activity and circadian rhythm, exemplary sleep disorders.

The hypothalamic-pituitary-adrenal (HPA) axis plays important roles in maintaining alertness and modulating sleep. Dysfunction of this axis at any level (CRH receptor, glucocorticoid receptor, or mineralocorticoid receptor) can disrupt sleep. Herein, we review normal sleep, normal HPA axis physiology and circadian rhythm, the effects of the HPA axis on sleep, as well as the effects of sleep on the HPA axis. We also discuss the potential role of CRH in circadian-dependent alerting, aside from its role in the stress response. Two clinically relevant sleep disorders with likely HPA axis dysfunction, insomnia and obstructive sleep apnea, are discussed. In insomnia, we discuss how HPA axis hyperactivity may be partially causal to the clinical syndrome. In obstructive sleep apnea, we discuss how HPA axis hyperactivity may be a consequence of the disorder and contribute to secondary pathology such as insulin resistance, hypertension, depression, and insomnia. Mechanisms by which cortisol can affect slow wave sleep are discussed, as is the role the HPA axis plays in secondary effects of primary sleep disorders.

Circadian Rhythm↗

PubMed2005

Chronic depression: medication (nefazodone) or psychotherapy (CBASP) is effective when the other is not.

CONTEXT: Although various strategies are available to manage nonresponders to an initial treatment for depression, no controlled trials address the utility of switching from an antidepressant medication to psychotherapy or vice versa. OBJECTIVE: To compare the responses of chronically depressed nonresponders to 12 weeks of treatment with either nefazodone or cognitive behavioral analysis system of psychotherapy (CBASP) who were crossed over to the alternate treatment (nefazodone, n = 79; CBASP, n = 61). DESIGN: Crossover trial. SETTING: Twelve academic outpatient psychiatric centers. PATIENTS: There were 140 outpatients with chronic major depressive disorder; 92 (65.7%) were female, 126 (90.0%) were white, and the mean age was 43.1 years. Thirty participants dropped out of the study prematurely, 22 in the nefazodone group and 8 in the CBASP group. INTERVENTIONS: Treatment lasted 12 weeks. The dosage of nefazodone was 100 to 600 mg/d; CBASP was provided twice weekly during weeks 1 through 4 and weekly thereafter. MAIN OUTCOME MEASURES: The 24-item Hamilton Rating Scale for Depression, administered by raters blinded to treatment, the Clinician Global Impressions-Severity scale, and the 30-item Inventory for Depressive Symptomatology-Self-Report. RESULTS: Analysis of the intent-to-treat sample revealed that both the switch from nefazodone to CBASP and the switch from from CBASP to nefazodone resulted in clinically and statistically significant improvements in symptoms. Neither the rates of response nor the rates of remission were significantly different when the groups of completers were compared. However, the switch to CBASP following nefazodone therapy was associated with significantly less attrition due to adverse events, which may explain the higher intent-to-treat response rate among those crossed over to CBASP (57% vs 42%). CONCLUSIONS: Among chronically depressed individuals, CBASP appears to be efficacious for nonresponders to nefazodone, and nefazodone appears to be effective for CBASP nonresponders. A switch from an antidepressant medication to psychotherapy or vice versa appears to be useful for nonresponders to the initial treatment.

Adult↗

PubMed2005

Duloxetine 60 mg once-daily in the treatment of painful physical symptoms in patients with major depressive disorder.

BACKGROUND: While emotional symptoms such as depressed mood and loss of interest have traditionally been considered to constitute the core symptoms of major depressive disorder (MDD), the prevalence and importance of painful physical symptoms such as back pain, abdominal pain, and musculoskeletal pain is becoming increasingly appreciated. Antidepressants possessing dual serotonin/norepinephrine (5-HT/NE) reuptake inhibition may demonstrate greater efficacy in the alleviation of pain. The efficacy of duloxetine, a balanced and potent dual reuptake inhibitor of 5-HT and NE, was evaluated within a cohort of depressed patients with associated painful physical symptoms. METHODS: In this multicenter, double-blind, placebo-controlled study, patients meeting DSM-IV criteria for MDD were randomized to receive placebo (N=141) or duloxetine 60 mg QD (N=141). Patients were required to have a 17-item Hamilton Rating Scale for Depression (HAMD17) total score 15, a Clinical Global Impression of Severity (CGI-S) score 4, and a Brief Pain Inventory (BPI) Average Pain score 2 at baseline. The primary efficacy measure was the BPI Average Pain score, while secondary measures included other BPI items, the HAMD17 total score, CGI-S, the Patient Global Impression of Improvement (PGI-I) scale, Visual Analog Scales (VAS) for pain, and the Symptom Questionnaire, Somatic Subscale (SQSS). Safety was evaluated by recording treatment-emergent adverse events (spontaneously reported), vital signs, and laboratory analytes. RESULTS: Mean changes in BPI Average Pain for duloxetine- and placebo-treated patients differed significantly at most visits, but only approached significance at endpoint p=0.066. For the main effect of treatment (pooling all visits), significant advantages for duloxetine-treated patients were found in 10 of 11 assessed BPI pain severity and pain interference items, in addition to VAS overall pain and back pain. Mean changes in pain measures for duloxetine-treated patients corresponded to improvements of 25-50%, compared with 19-39% for placebo. Mean changes at endpoint in depression rating scales (HAMD17, CGI-S, PGI-I) did not differ significantly between duloxetine and placebo treatment groups due to unusually high placebo response. The magnitude of placebo treatment effects (as measured by HAMD17 total score and Maier subscale) was significantly smaller in patients with 1 previous depressive episode, compared to those patients with no previous episodes. In patients with 1 previous depressive episode the advantage of duloxetine over placebo was similar to previous studies. Rates of discontinuation due to adverse events were 14.2% vs. 2.1% for duloxetine and placebo, respectively p<0.001. Treatment-emergent adverse events reported at a significantly higher rate by duloxetine-treated patients included nausea, dry mouth, fatigue, and decreased appetite. CONCLUSIONS: In this study, duloxetine (60 mg QD) was shown to be an effective treatment for the painful physical symptoms which are frequently associated with depression. Improvements in pain severity occurred independently of changes in depressive symptom severity.

Administration, Oral↗

PubMed2005

Monoamine oxidase and catechol-o-methyltransferase enzyme activity and gene expression in response to sustained glucocorticoids.

We previously reported changes in DA neurochemical estimates after sustained corticosterone (CORT) administration or adrenalectomy (ADX) that are consistent with glucocorticoid-induced inhibition of DA metabolism. The present investigation measured monoamine oxidase type A (MAO-A), type B (MAO-B) and catechol-o-methyltransferase (COMT) activity by enzymatic assay and levels of gene expression by real-time quantitative polymerase chain reaction (rt-PCR) in tissues from sham, ADX, or ADX+CORT-replaced Lewis rats. One week of ADX had no significant effect on either enzyme activity or gene expression for any of the three enzymes examined in the medial prefrontal cortex, striatum, or liver. One week of CORT administration (100mg-21 day release pellet) in ADX rats produced statistically significant decreases in MAO-A enzyme activity and MAO-B gene expression in the liver but no significant changes for any of the three enzymes in either activity or gene expression in the medial prefrontal cortex or striatum. The results do not support inhibition of DA metabolism as a mechanism by which glucocorticoids influence DA-mediated behaviors.

Adrenalectomy↗