The effects of diazepam on sleep, and on the nocturnal release of growth hormone, prolactin, ACTH and cortisol

Hypothalamic-pituitary-adrenocortical axis: neuropsychiatric aspects

Evidence of aberrant hypothalamic-pituitary-adrenocortical (HPA) activity in many psychiatric disorders, although not universal, has sparked long-standing interest in HPA hormones as biomarkers of disease or treatment response. HPA activity may be chronically elevated in melancholic depression, panic disorder, obsessive-compulsive disorder, and schizophrenia. The HPA axis may be more reactive to stress in social anxiety disorder and autism spectrum disorders. In contrast, HPA activity is more likely to be low in PTSD and atypical depression. Antidepressants are widely considered to inhibit HPA activity, although inhibition is not unanimously reported in the literature. There is evidence, also uneven, that the mood stabilizers lithium and carbamazepine have the potential to augment HPA measures, while benzodiazepines, atypical antipsychotics, and to some extent, typical antipsychotics have the potential to inhibit HPA activity. Currently, the most reliable use of HPA measures in most disorders is to predict the likelihood of relapse, although changes in HPA activity have also been proposed to play a role in the clinical benefits of psychiatric treatments. Greater attention to patient heterogeneity and more consistent approaches to assessing treatment effects on HPA function may solidify the value of HPA measures in predicting treatment response or developing novel strategies to manage psychiatric disease.

Cortisol response to diazepam: its relationship to age, dose, duration of treatment, and presence of generalized anxiety disorder

OBJECTIVE

Acute diazepam administration has been shown to decrease plasma cortisol levels consistent with decreased activity of the hypothalamic-pituitary-adrenal axis, especially in individuals experiencing stress. However, the effects of chronic diazepam treatment on cortisol have been less studied, and the relationship to age, anxiety, duration of treatment, and dose are not well understood.

METHOD

This double-blind placebo-controlled study examined acute and chronic effects of diazepam on plasma cortisol levels in young (19-35 years) and elderly (60-79 years) individuals with and without generalized anxiety disorder (GAD). Subjects received single oral challenges of placebo or diazepam (2.5 mg or 10 mg) in a placebo-controlled cross-over design, followed by 3 weeks of chronic daily treatment with 2.5 mg or 10 mg diazepam or placebo taken at 10 p.m., and then by a final acute challenge with a single oral dose of the same study medication received during chronic treatment.

RESULTS

The elderly experienced significant reductions in plasma cortisol levels compared to placebo both in the initial challenge and during chronic treatment, but the young did not. However, cortisol response to drug was comparable in both groups. Final challenge did not produce any significant cortisol effects in either group and the cortisol response in the elderly was significantly reduced compared to the initial challenge. GAD status was not a factor in plasma cortisol responses to diazepam.

CONCLUSIONS

Diazepam reduced cortisol both acutely and during chronic treatment, but not during final challenge, consistent with some tolerance development. This effect was most apparent in the elderly compared with the young adults and was not modulated by GAD status or dosage, and was not related to drug effects on performance and on self-ratings of sedation and tension.

Interdose elevation in plasma cortisol during chronic treatment with alprazolam but not lorazepam in the elderly

Benzodiazepines (BZPs) have been shown to reduce hypothalamic-pituitary-adrenal (HPA) axis activity acutely in normal humans. In contrast, the effects of chronic BZP treatment on the HPA axis have not been well studied, especially in the geriatric population. This study examined the acute and chronic effects (3 weeks) of alprazolam and lorazepam on plasma cortisol in 68 subjects (60-83 years) who received 0.25 or 0.50 mg b.i.d. alprazolam, or 0.50 or 1.0 mg b.i.d. lorazepam, or placebo orally according to a randomized, double-blind, placebo-controlled parallel design. Memory assessment and blood samples for plasma cortisol were obtained prior to the morning dose on days 0, 7, 14, and 21, and at 1, 2.5, and 5 h postdrug on days 0 and 21. Assessments of anxiety and depression were carried out at days 0, 7, 14, and 21 before drug administration. Plasma cortisol was affected compared to placebo only by the 0.5 mg alprazolam dose. During the first and the last day of treatment, there was a significant drop in cortisol at 2.5 h after alprazolam compared to placebo. The predose cortisol levels increased significantly during chronic alprazolam treatment, and correlations were found between these cortisol changes and changes in depression, anxiety, and memory scores. These findings suggest that even a short period of chronic treatment with alprazolam, but not lorazepam, may result in interdose HPA axis activation in the elderly, consistent with drug withdrawal. If confirmed, this effect may contribute to an increased risk for drug escalation and dependence during chronic alprazolam treatment.

Benzodiazepines and anterior pituitary function

Benzodiazepines (BDZ) are one of the most prescribed classes of drugs because of their marked anxiolytic, anticonvulsant, muscle relaxant and hypnotic effects. The pharmacological actions of BDZ depend on the activation of 2 specific receptors. The central BDZ receptor, present in several areas of the central nervous system (CNS), is a component of the GABA-A receptor, the activation of which increases GABAergic neurotransmission and is followed by remarkable neuroendocrine effects. The peripheral benzodiazepine receptors (PBR), structurally and functionally different from the GABA-A receptor, have been shown in peripheral tissues but also in the CNS, in both neurones and glial cells, and in the pituitary gland. BDZ receptors bind to a family of natural peptides called endozepines, firstly isolated from neurons and glial cells in the brain and then in several peripheral tissues as well. Endozepines modulate several central and peripheral biological activities, including some neuroendocrine functions and synthetic BDZ are likely to mimic them, at least partially. BZD, especially alprazolam (AL), possess a clear inhibitory influence on the activity of the HPA axis in both animals and humans. This effect seems to be mediated at the hypothalamic and/or suprahypothalamic level via suppression of CRH. The strong negative influence of AL on hypothalamicpituitary-adrenal (HPA) axis agrees with its peculiar efficacy in the treatment of panic disorders and depression. BZD have also been shown to increase GH secretion via mechanisms mediated at the hypothalamic or supra-hypothalamic level, though a pituitary action cannot be ruled out. Besides the impact on HPA and somatotrope function, BDZ also significantly affect the secretion of other pituitary hormones, such as gonadotropins and PRL, probably acting through GABAergic mediation in the hypothalamus and/or in the pituitary gland. In all, BDZ are likely to represent a useful tool to investigate GABAergic activity and clarify its role in the neuroendocrine control of anterior pituitary function; their usefulness probably overrides what had been supposed before.

Long-term caffeine inhibits Ehrlich ascites carcinoma cell-induced induction of central GABAergic activity

Long-term administration (for 22-27 consecutive days) of caffeine (20 mg/kg/day p.o) developed tolerance to this drug by upregulating the central GABAergic activity. Development of Ehrlich ascites carcinoma (EAC) cell induced the whole brain GABAergic activity. But pretreatment of caffeine and continuation of its treatment in the course of development of EAC cells restored the EAC cell-induced change of GABAergic activity to control values. Thus, it may be concluded that caffeine (adenosine receptor antagonist) suppresses the EAC cell-induced induction of whole brain GABAergic activity in mice.

Bretazenil modulates sleep EEG and nocturnal hormone secretion in normal men

Preclinical data suggest that the imidazodiazepinone derivative bretazenil (Ro 16-6028) has anxiolytic and anticonvulsant properties with only weak sedative effects. We examined the influence of oral administration of 1 mg bretazenil on the sleep EEG and the concomitant nocturnal secretion of cortisol, growth hormone and prolactin in ten healthy young men. After bretazenil we found a significant increase in stage 2 sleep and a significant reduction in stage 3 sleep. REM latency was prolonged. Spectral analysis of sleep-EEG power revealed a decrease in delta and in theta power and an increase in sigma power. We found no significant influence on sleep onset latency or on intermittent wakefulness. Bretazenil prompted a significant decrease in cortisol secretion and a significant increase in prolactin release. It had no major influence on growth hormone secretion.

Flumazenil exerts intrinsic activity on sleep EEG and nocturnal hormone secretion in normal controls

The physiological function of benzodiazepine (BDZ) receptors includes regulation of sleep and neuroendocrine activity. Most of the pharmacological effects of BDZ are blocked by flumazenil. However, recent neurological and behavioral studies suggest that flumazenil has its own central intrinsic activity. This issue was addressed in a study of the sleep EEG and the nocturnal secretion of growth hormone and cortisol in ten normal male controls, who were given flumazenil either alone or in combination with the BDZ agonist midazolam, placebo and midazolam alone. Flumazenil prompted an increase in sleep onset latency, a decrease in slow wave sleep and an increase in wakefulness. Plasma cortisol concentrations after flumazenil administration were lower than after midazolam. Both flumazenil and midazolam decreased nocturnal growth hormone secretion. After simultaneous application of both BDZ receptor ligands the growth hormone blunting was amplified. Our study demonstrates that at the level of the sleep EEG and neuroendocrine activity flumazenil is capable of exerting both agonistic and inverse agonistic or antagonistic effects.

Benzodiazepines antagonize central corticotropin releasing hormone-induced suppression of natural killer cell activity

Benzodiazepines have anxiolytic properties and attenuate behavioral stress responses induced by corticotropin releasing hormone (CRH). To evaluate the effect of benzodiazepines on CRH-induced immune suppression, potent centrally acting benzodiazepines were administered prior to central infusion of CRH (i.c.v.; 1.0 microgram). CRH induced a significant (P < 0.01) reduction of splenic natural killer cell activity which was completely antagonized by pretreatment with either diazepam or alprazolam.

Alterations to plasma melatonin and cortisol after evening alprazolam administration in humans

Six healthy volunteers were given a 2-mg dose of alprazolam at 21:00 h and hourly blood samples were collected until 08:00 h the following morning. A control night of hourly blood sampling was undertaken 7 days before Plasma was analyzed for melatonin, cortisol, and alprazolam concentrations. Melatonin concentrations were significantly suppressed by alprazolam at 23:00, midnight, 01:00, 06:00, and 07:00 h. A trend toward suppression was evident from 02:00 to 05:00 h. Cortisol concentrations were also suppressed by alprazolam at several times throughout the night (01:00-04:00 h). Plasma alprazolam levels showed a peak at 3 h and remained relatively high 19-20 h after the dose. The significance of melatonin suppression by alprazolam is discussed in terms of benzodiazepine binding sites and GABA minergic transmission in the human pineal gland, suprachiasmatic nuclei, and retina. Plasma cortisol suppression has been reported for other benzodiazepine drugs, but conflicting data exist for alprazolam. The present results do not support the proposed inhibitory effect of melatonin on the hypothalamic-pituitary-adrenal (HPA)-axis. It is suggested that there is no simple direct relationship between melatonin and the HPA axis in humans.

Adrenocorticotropin hormone response to diazepam in healthy young men

The effects of diazepam (DZ) infusions on changes in adrenocorticotropin hormone (ACTH) are a source of debate. In this study, 66 healthy young adult men were evaluated for changes in plasma ACTH after intravenous infusions with placebo, 0.12 mg/kg and 0.20 mg/kg of DZ. After the higher DZ dose, 85% of the subjects demonstrated a decrease in ACTH of 20% or more, with the nadir occurring between 30 and 60 min postinfusion and values returning to baseline levels by 180 min. These results support the conclusion that at the clinically relevant doses used here, DZ infusions are associated with a significant decrease in ACTH.

Effects of chronic alprazolam treatment on plasma concentrations of glucocorticoids, thyroid hormones, and testosterone in cardiomyopathic hamsters

In the first of two experiments, young male cardiomyopathic hamsters were injected intraperitoneally twice a day for 29 days with 8 mg alprazolam/kg body weight or saline. Three hours after the same injections on day 30, they were sacrificed and plasma hormone levels were measured. Alprazolam increased cortisol, total glucocorticoid and triiodothyronine levels. It did not affect corticosterone, thyroxine or testosterone levels. The same protocol was used in a second experiment, except the controls received vehicle and a third group was treated with 48 mg diazepam/kg body weight. Alprazolam again increased cortisol and total glucocorticoid levels, but not those of corticosterone. On the other hand, diazepam increased both cortisol and corticosterone levels. These experiments suggest that chronic benzodiazepine treatment can affect adrenocortical function and perhaps some aspects of thyroid function.

Interaction between GABAergic neurotransmission and rat hypothalamic corticotropin-releasing hormone secretion in vitro

Corticotropin-releasing hormone (CRH) has been considered a major coordinator of the overall physical and behavioral response to stress. Moreover, prolonged hypersecretion of CRH has been implicated in the pathogenesis of disorders characterized by anxiety and/or depression. Drugs acting through the gamma-aminobutyric acid/benzodiazepine (GABA/BZD) receptor system have anxiolytic and/or antidepressant properties whereas benzodiazepine inverse agonists cause anxiety and stimulate the pituitary-adrenal axis in vivo. To examine the involvement of the GABA/BZD system in the regulation of hypothalamic CRH secretion, we studied the effects of various agonists and antagonists of GABAA and GABAB receptors using a sensitive rat hypothalamic organ culture with radioimmunoassayable CRH (IR-rCRH) as endpoint. The GABAA and GABAB receptor agonist GABA inhibited serotonin (5-HT)-induced IR-rCRH secretion from 10(-9) to 10(-6) M, but failed to do so at 10(-5) M. The GABAA receptor agonist muscimol was a weak inhibitor of 5-HT-induced IR-rCRH secretion, being effective only at the concentration of 10(-6) M. In contrast, the specific GABAB receptor agonist baclofen was able to inhibit 5-HT-induced IR-rCRH secretion from 10(-7) to 10(-5) M. The rank of potency was thus, GABA much greater than baclofen greater than muscimol. Bicuculline, a GABAA receptor antagonist, partially reversed the inhibitory effects of GABA. Diazepam, a classic benzodiazepine which interacts with the benzodiazepine-site of the GABAA receptor complex, inhibited 5-HT-induced IR-rCRH secretion from 3.3 X 10(-9) to 10(-5) M, an effect that could be reversed by the BZD inactive ligand Ro15-1788.(ABSTRACT TRUNCATED AT 250 WORDS)

Basal and post-dexamethasone cortisol and prolactin concentrations in depressed and non-depressed patients with chronic pain syndromes

To assess the behavior of two putative neuroendocrine markers of depression in chronic pain, the authors determined plasma cortisol and prolactin concentrations before and after dexamethasone in 52 hospitalized male chronic pain patients. Their psychiatric diagnoses by Research Diagnostic Criteria (RDC) were: major depression (N = 24; 44.2%), minor depression (N = 10; 19.2%), another RDC diagnosis (N = 7; 13.5%) and not mentally ill (N = 12; 21.6%). Failure to suppress cortisol after dexamethasone (a positive DST) occurred in 43.5% of those with major depression, 20% of those with minor depression, 42.8% of those with other psychiatric diagnoses and in 8.3% of patients without a psychiatric disorder. The frequency of non-suppression was significantly different only for patients with major depression compared to those without diagnosable psychiatric disorder. Mean basal cortisol concentrations at 08.00, 16.00 and 23.00 h did not differ among psychiatric diagnostic groups of pain patients, or between these groups and healthy volunteers. Levels of prolactin, but not cortisol, were significantly correlated with the severity of mood disturbances. These findings suggest strategies using multiple endocrine markers to distinguish pain from depression should be explored.

Suppression of plasma cortisol after oral administration of oxazepam in man

In seven healthy male subjects plasma cortisol was measured at 20 min intervals from 07.00 to 13.00 h, during a drug free control test and after oral administration of 30 and 60 mg oxazepam. A significant suppression of the plasma cortisol levels for about 2 h after 30 mg oxazepam, and for about 3 h after 60 mg oxazepam was observed. The suppression wore off before the oxazepam plasma concentration started to decline significantly.

Are poor sleepers changed into good sleepers by hypnotic drugs?

Sleep can be measured by subjective ratings, electrophysiological recordings and by the physiological and biochemical changes occurring with sleep. Using these methods, we can select those who rate their sleep as unsatisfactory and those who feel fully satisfied by their sleep. Electrophysiological recordings of sleep show that there are relatively small differences between these good and poor sleepers: poor sleepers sleep less than good sleepers, but not as little as they think. However, the complaints of poor sleepers that they feel unrestored by their sleep should not be dismissed, for investigations employing the tools of physiology and biochemistry have revealed differences between good and poor sleepers that suggest that the sleep of poor sleepers may indeed be less restorative. The actions of hypnotic drugs on sleep can be similarly investigated. Preliminary findings suggest that hypnotic drugs may reverse some of the detrimental metabolic concomitants of poor sleep.

[Effects of carbamazepine on EEG. Neuroendocrinological and psychometric examinations (author's transl)]

The effects of carbamazepine on EEG, sleep-related release of growth hormone and prolactin, and on psychometric parameters were studied in ten healthy volunteers under controlled double-blind cross-over conditions. Acute application of 300 and 600 mg Tegretal resulted in constant blood levels around 3.0 and 5.5 microgram/ml respectively during the test periods of 5 and 7 h. Computerized EEG analysis according to Hjorth, revealed an occipital increase of amplitude and a decrease of mean frequency, but a frontal increase of frequency, a pattern similar to that of the tricyclic antidepressants. The polygraphic sleep pattern showed a significant decrease of sleep latency after 600 mg carbamazepine without changes of other sleep parameters. The sleep-related release of growth hormone after 600 mg carbamazepine showed a faster increase during the first sleep cycle; the profile of prolactin release, however, and the overall nocturnal secretion of both hormones were not affected. After 300 mg carbamazepine the psychometric tests revealed no significant effects on performance, but reflected an improvement of mood on self rating scales.