Escape from dexamethasone suppression: Possible role of an impaired inhibitory opioid mechanism

1. 1. Several lines of evidence indicate that the activity of the hypothalamus-pituitary-adrenal (HPA) axis in depression is disinhibited.2. 2. Escape from dexamethasone suppression, although not limited to is more frequent in patients with endogenous depression compared to normals or patients with other psychiatric diagnoses.3. 3. Norepinephrine, serotonin and acetylcholine have been implicated in the pathophysiology of this neuroendocrine abnormality.4. 4. Morphine, 5 mg intravenously, suppressed Cortisol secretion in healthy volunteers (n = 4) and the majority of 32 psychiatric inpatients.5. 5. However, patients with endogenous depression abnormal dexamethasone suppression test results show early resumption (escape) of cortisol secretion following the initial suppression induced by morphine.6. 6. It is concluded that the pathophysiology of this neuroendocrine abnormality is not limited to classical neurotransmitter-HPA axis interaction but that it also involves opioid inhibitory mechanisms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25429/1/0000878.pd

Morphine inhibits cortisol and stimulates prolactin secretion in man

The role of opioids in endocrine regulation has been the subject of numerous studies. Surprisingly, however, the acute endocrine effects of morphine on basal hormonal levels in man have not been adequately documented. We report here the effects of intravenous morphine (5 mg) on plasma cortisol and prolactin. Fourteen healthy volunteers (nine male, five female) received morphine at 0930 hr. Blood samples were collected immediately before and 30, 60, 90, 120 and 180 min after the injection. In six of the male subjects the procedure was repeated with a placebo (normal saline) injection. Morphine stimulated prolactin release. There was a trend for a greater response in females compared to male subjects. Cortisol secretion was markedly suppressed by morphine. In sharp contrast to the results obtained with placebo, cortisol levels following morphine declined progressively at a rate consistent with the half-life of cortisol. This downward trend of cortisol values continued uninterrupted for the duration of the experiment in all 14 subjects. These results are consistent with the presence of an inhibitory opioid mechanism in the human hypothalamopituitary-adrenal axis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25007/1/0000434.pd

Comparison of early and delayed inpatient dexamethasone suppression tests

Ninety-five inpatients completed a dexamethasone suppression test (DST) within 72 hours after admission and again after at least 1 week of medication-free hospital care. The frequency of cortisol nonsuppression in patients with endogenous depression (ED) was high and not significantly different at both tests. In patients with diagnoses other than ED, the higher rate of cortisol nonsuppression at the first DST was associated with a significant decrease in test specificity. Change in postdexamethasone cortisol levels at repeat testing was associated with a decrease in depressive symptomatology, but was not related to weight change during hospitalization.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28066/1/0000509.pd

Prolactin response to TRH in depression

We studied the prolactin response to TRH in 53 unmedicated psychiatric inpatients. The prolactin response of females was significantly greater than the response of male subjects. There was no significant difference in the prolactin response to TRH between depressed patients and those with other psychiatric diagnoses. There was no significant relationship between the prolactin response to TRH and the severity of depression, the TSH response to TRH or the resistance to suppression of cortisol secretion by dexamethasone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26341/1/0000428.pd

Economic evaluation of waste management options for remote areas

Municipal solid waste management is one of the most pressing issues of today’s societies as the consequences of growing economies in waste generation have serious effects on the environment. These effects are even more difficult to tackle in remote areas such as islands or mountainous areas, both types of which are dominant in the Greek topography. More specifically, the current situation is compared financially to a municipal solid waste transportation scenario for treatment in large scale facilities. A statistical analysis of population data and waste generation in the past years will be used to predict the future waste generation in the examined regions. This research concentrates on areas where sanitary landfills are either obsolete or non-existent, and where the common practice is using open dumps. Using geographical data in conjunction with satellite information and some rough estimations for fuel cost in the future, transportation costs are calculated. Advantages of the examined scenario are not limited to monetary terms, but also include social gains for these regions along with new job opportunities. Potential benefits arising from the concentration of transported waste will be explored, and the scope for further research will be presented

A monetary analysis of the Drachma/ECU exchange rate determination, 1980-1991

The validity of the monetary approach to the Drachma/ECU exchange rate determination is investigated through cointegration, impulse response and variance decomposition analysis. The empirical results reported confirm recent findings that the monetary approach may be interpreted as a long-run equilibrium condition with highly complex short-run dynamics.Exchange rate · cointegration · VAR · Greece

Neuroendocrine effects of l -tryptophan and dexamethasone

An infusion of l -tryptophan was administered twice to five healthy male volunteers, once after pretreatment with dexamethasone 1 mg the previous evening and once after no dexamethasone. Cortisol, prolactin, and growth hormone levels were measured, and the responses to l -tryptophan were compared with those seen after an infusion of l -threonine. l -tryptophan did not produce cortisol secretion after dexamethasone, but prolactin and growth hormone responses were noticed. The results demonstrate a stimulatory effect of l -tryptophan on prolactin and growth hormone secretion, and the former is facilitated by pretreatment with dexamethasone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46440/1/213_2004_Article_BF00175195.pd

Platelet alpha2 adrenoreceptors are decreased in number after antidepressant therapy

1. 1. Specific binding of 3H-clonidine to alpha2 adrenoreceptors upon human blood platelet membranes is increased in patients with major depressive disorder (endogenous depression).2. 2. Specific binding of 3H-yohimbine to the platelet adrenoreceptor is not altered in endogenously depressed patients.3. 3. Other psychiatric disorders are not associated with alterations in the specific binding of either 3H-clonidine or 3H-yohimbine. In patients with severe congestive heart failure or with symptomatic coronary artery disease the number of platelet alpha2 adrenoreceptors is actually decreased.4. 4. Treatment of endogenously depressed patients with tricyclic antidepressants, lithium salts or electroconvulsive therapy results in a decrease in the number of alpha2 adrenoreceptors on blood platelet membranes.5. 5. These studies suggest that a supersensitivity of the alpha2 adrenoreceptor might exist in patients with endogenous depression and that effective forms of therapy lead to a decrease in the number of neural alpha2 adrenoreceptors which is reflected by a decrease in the number of these receptors upon blood platelet membranes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25388/1/0000837.pd

Tricyclic antidepressant drug treatment decreases [alpha]2-adrenoreceptors on human platelet membranes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24483/1/0000758.pd