Neuroactive steroid changes in response to challenge with the panicogenic agent pentagastrin

Effects of low doses of the novel dehydroepiandrosterone (DHEA) derivative BNN27 in rat models of anxiety

RATIONALE

Several lines of evidence indicate that the neurosteroid dehydroepiandrosterone (DHEA) is involved in anxiety. BNN27 is a new DHEA derivative lacking steroidogenic effects. The beneficial effects exerted by BNN27 in preclinical models of schizophrenia and memory disorders have been recently reported.

OBJECTIVES

The present study was designed to investigate the effects of this DHEA novel analog on anxiety-like behavior in rats.

METHODS

To this end, the light/dark box, the open field, the contextual fear conditioning, and the excessive self-grooming induced by the serotonin 5-HT2c receptor agonist mCPP tests were utilized.

RESULTS

Animals treated acutely with BNN27 (1, 3, and 6 mg/kg) dose dependently spent more time in the bright compartment of the light/dark box and in the central zone of the open field with respect to their vehicle-treated cohorts. Further, BNN27 reduced freezing behavior and weakened the mCPP-induced excessive self-grooming.

CONCLUSIONS

Our data indicate that BNN27 is a highly potent anxiolytic agent, as in all studied paradigms it showed anxiolytic-like effects in male rats.

Pituitary-adrenal axis hormones in early-onset versus late-onset panic disorder

OBJECTIVE

It has been hypothesised that early-onset panic disorder (PD) may constitute a biologically distinct subtype of PD, but the few relevant data are inconclusive. We systematically explored for potential psychopathological and hormonal differences between early-onset (age at onset ≤ 27 years) versus late-onset PD, in consecutively-referred, medication-free, acutely-ill PD outpatients, moreover without comorbid mental disorders except agoraphobia (N = 54; age = 32.3 ± 7.5 years; early-onset = 27; females = 38).

METHODS

Hormones assessed (plasma levels) included adrenocorticotropic hormone (ACTH), cortisol and dehydroepiandrosterone sulphate (DHEAS). Psychopathological measures included panic attacks' number during last three weeks, the Agoraphobic Cognitions and the Body Sensations Questionnaires and the Hamilton Anxiety Rating Scale.

RESULTS

Early-onset PD patients - compared to their late-onset counterparts - had longer duration of the disease. The two onset-groups demonstrated similar panic and anxiety symptoms and similar ratios of smokers/never-smokers. However, early-onset patients demonstrated significantly greater ACTH and DHEAS levels and higher (marginally significant) cortisol levels than the late-onset patients. Moreover, in the early-onset patients only, significant positive correlations emerged between ACTH levels and the severity of both panic and anxiety symptomatology.

CONCLUSIONS

These findings suggest that the two onset-groups demonstrate significant differences in the hypothalamic-pituitary-adrenal axis functioning, at least when acutely-ill.Key pointsEarly-onset panic disorder (EOPD) may differ biologically from late-onset PD (LOPD).EOPD was correlated with greater adrenocorticotropic hormone (ACTH) plasma levels.EOPD was correlated with greater dehydroepiandrosterone sulphate plasma levels.In EOPD only, ACTH levels were positively correlated with panic and anxiety symptoms.

Sex differences in progestogen- and androgen-derived neurosteroids in vulnerability to alcohol and stress-related disorders

Stress and trauma exposure disturbs stress regulation systems and thus increases the vulnerability for stress-related disorders which are characterized by negative affect, including major depressive disorder, anxiety disorders and posttraumatic stress disorder. Similarly, stress and trauma exposure results in increased vulnerability to problematic alcohol use and alcohol use disorder, especially among women, who are more likely to drink to cope with negative affect than their male counterparts. Given these associations, the relationship between stress-related disorders and alcohol use is generally stronger among women leading to complex comorbidities across these disorders and alcohol misuse. This review highlights the therapeutic potential for progestogen- and androgen-derived neurosteroids, which affect both stress- and alcohol-related disorders, to target the overlapping symptoms related to negative affect. This article is part of the special issue on 'Vulnerabilities to Substance Abuse.'

Lack of specific association between panicogenic properties of caffeine and HPA-axis activation. A placebo-controlled study of caffeine challenge in patients with panic disorder

A subgroup of patients with Panic Disorder (PD) exhibits increased sensitivity to caffeine administration. However, the association between caffeine-induced panic attacks and post-caffeine hypothalamic-pituitary-adrenal (HPA)-axis activation in PD patients remains unclear. In a randomized, double-blind, cross-over experiment, 19 PD patients underwent a 400-mg caffeine-challenge and a placebo-challenge, both administered in the form of instant coffee. Plasma levels of adrenocorticotropic hormone (ACTH), cortisol and dehydroepiandrosterone sulfate (DHEAS) were assessed at both baseline and post-challenge. No patient panicked after placebo-challenge, while nine patients (47.3%) panicked after caffeine-challenge. Placebo administration did not result in any significant change in hormones' plasma levels. Overall, sample's patients demonstrated significant increases in ACTH, cortisol, and DHEAS plasma levels after caffeine administration. However, post-caffeine panickers and non-panickers did not differ with respect to the magnitude of the increases. Our results indicate that in PD patients, caffeine-induced panic attacks are not specifically associated with HPA-axis activation, as this is reflected in post-caffeine increases in ACTH, cortisol and DHEAS plasma levels, suggesting that caffeine-induced panic attacks in PD patients are not specifically mediated by the biological processes underlying fear or stress. More generally, our results add to the evidence that HPA-axis activation is not a specific characteristic of panic.

Multifunctional aspects of allopregnanolone in stress and related disorders

Allopregnanolone (3α-hydroxy-5α-pregnan-20-one) is a major cholesterol-derived neurosteroid in the central nervous system and is synthesized from progesterone by steroidogenic enzymes, 5α-reductase (the rate-limiting enzyme) and 3α-hydroxysteroid dehydrogenase. The pathophysiological role of allopregnanolone in neuropsychiatric disorders has been highlighted in several investigations. The changes in neuroactive steroid levels are detected in stress and stress-related disorders including anxiety, panic and depression. The changes in allopregnanolone in response to acute stressor tend to restore the homeostasis by dampening the hyper-activated HPA axis. However, long standing stressors leading to development of neuropsychiatric disorders including depression and anxiety are associated with decrease in the allopregnanolone levels. GABAA receptor complex has been considered as the primary target of allopregnanolone and majority of its inhibitory actions are mediated through GABA potentiation or direct activation of GABA currents. The role of progesterone receptors in producing the late actions of allopregnanolone particularly in lordosis facilitation has also been described. Moreover, recent studies have also described the involvement of other multiple targets including brain-derived neurotrophic factor (BDNF), glutamate, dopamine, opioids, oxytocin, and calcium channels. The present review discusses the various aspects of allopregnanolone in stress and stress-related disorders including anxiety, depression and panic.

Changes in neuroactive steroid secretion associated with CO2-induced panic attacks in normal individuals

Neuroactive steroids modulate anxiety in experimental animals and possibly in humans. The secretion of these compounds has been found to be altered in panic disorder (PD), with such alterations having been suggested to be a possible cause or effect of panic symptomatology. Panic-like attacks can be induced in healthy individuals by administration of panicogenic agents or by physical procedures, and we have now measured the plasma concentrations of neuroactive steroids in such individuals before, during, and after panicogenic inhalation of CO2 in order to investigate whether abnormalities of neuroactive steroid secretion might contribute to the pathogenesis of PD. Fifty-nine psychologically and physically healthy subjects, including 42 women (11 in the follicular phase of the menstrual cycle, 14 in the luteal phase, and 17 taking contraceptive pills) and 17 men, who experienced a panic-like attack on previous exposure to 7% CO2 were again administered 7% CO2 for 20min. Thirty-three of these individuals (responders) again experienced a panic-like attack, whereas the remaining 26 subjects did not (nonresponders). All subjects were examined with the VAS-A and PSL-III-R scales for anxiety and panic symptomatology before and after CO2 inhalation. The plasma concentrations of progesterone, 3α,5α-tetrahydroprogesterone (3α,5α-THPROG=allopregnanolone), 3α,5α-tetrahydrodesoxycorticosterone (3α,5α-THDOC), dehydroepiandrosterone (DHEA), and cortisol were measured 15min and immediately before the onset of CO2 administration as well as immediately, 10, 30, and 50min after the end of CO2 inhalation. Neuroactive steroids were measured in the laboratory of Prof. Biggio in Cagliari, Sardinia, Italy. Neurosteroid levels did not change significantly in both responders and nonresponders before, during, or after CO2 inhalation. These data suggest that neuroactive steroid concentrations before, during, or after CO2 inhalation do not seem to correlate with panic symptomatology during panic-like attacks in subjects not affected by PD, and they therefore do not support the notion that abnormalities in neuroactive steroid secretion are either a cause or an effect of such attacks.

Progesterone facilitates exploration, affective and social behaviors among wildtype, but not 5α-reductase Type 1 mutant, mice

Progesterone (P4) facilitates exploration, anxiety and social behaviors in estrogen (E2)-primed mice. Some of these effects may be due to actions of its 5α-reduced metabolite, 5α-pregnan-3α-ol-20-one (3α,5α-THP). In order to address the role of P4 and its metabolite, 3α,5α-THP, a mouse model was utilized. We hypothesized that if P4's metabolism to 3α,5α-THP is essential to facilitate exploratory, anti-anxiety and social behaviors of mice, then wildtype, but not 5α-reductase knockout (5α-RKO), mice will have greater expression of these behaviors. Experiment 1: Mice were ovariectomized (ovx), E2-primed and administered P4 (0, 125, 250, or 500μg) subcutaneously and then tested 4h later in a battery of tasks: open field, elevated plus maze, and social interaction. Experiment 2: Ovx, E2-primed mice were administered P4 (4mg/kg), 3α,5α-THP (4mg/kg), medroxyprogesterone acetate (MPA, which does not convert to 3α,5α-THP; 4mg/kg), or vehicle subcutaneously and tested 4h later. There was a dose-dependent effect of P4 to wildtype, but not 5α-RKO, mice. Neither wildtype, nor 5α-RKO, mice had increased exploration, anti-anxiety or pro-social behavior with MPA administration. Progesterone only exerted effects on anti-anxiety behavior, and increased 3α,5α-THP in the prefrontal cortex and hippocampus, when administered to wildtype mice. 3α,5α-THP to both WT and 5α-RKO mice increased exploration, anti-anxiety and social interaction and 3α,5α-THP levels in the hippocampus and prefrontal cortex. Thus, metabolism of P4 by the 5α-reductase enzyme may be essential for enhancement of these behaviors.

Effects and Mechanisms of 3α,5α,-THP on Emotion, Motivation, and Reward Functions Involving Pregnane Xenobiotic Receptor

Progestogens [progesterone (P(4)) and its products] play fundamental roles in the development and/or function of the central nervous system during pregnancy. We, and others, have investigated the role of pregnane neurosteroids for a plethora of functional effects beyond their pro-gestational processes. Emerging findings regarding the effects, mechanisms, and sources of neurosteroids have challenged traditional dogma about steroid action. How the P(4) metabolite and neurosteroid, 3α-hydroxy-5α-pregnan-20-one (3α,5α-THP), influences cellular functions and behavioral processes involved in emotion/affect, motivation, and reward, is the focus of the present review. To further understand these processes, we have utilized an animal model assessing the effects, mechanisms, and sources of 3α,5α-THP. In the ventral tegmental area (VTA), 3α,5α-THP has actions to facilitate affective, and motivated, social behaviors through non-traditional targets, such as GABA, glutamate, and dopamine receptors. 3α,5α-THP levels in the midbrain VTA both facilitate, and/or are enhanced by, affective and social behavior. The pregnane xenobiotic receptor (PXR) mediates the production of, and/or metabolism to, various neurobiological factors. PXR is localized to the midbrain VTA of rats. The role of PXR to influence 3α,5α-THP production from central biosynthesis, and/or metabolism of peripheral P(4), in the VTA, as well as its role to facilitate, or be increased by, affective/social behaviors is under investigation. Investigating novel behavioral functions of 3α,5α-THP extends our knowledge of the neurobiology of progestogens, relevant for affective/social behaviors, and their connections to systems that regulate affect and motivated processes, such as those important for stress regulation and neuropsychiatric disorders (anxiety, depression, schizophrenia, drug dependence). Thus, further understanding of 3α,5α-THP's role and mechanisms to enhance affective and motivated processes is essential.

Neuroactive steroids in affective disorders: target for novel antidepressant or anxiolytic drugs?

In the past decades considerable evidence has emerged that so-called neuroactive steroids do not only act as transcriptional factors in the regulation of gene expression but may also alter neuronal excitability through interactions with specific neurotransmitter receptors such as the GABA(A) receptor. In particular, 3α-reduced neuroactive steroids such as allopregnanolone or allotetrahydrodeoxycorticosterone have been shown to act as positive allosteric modulators of the GABA(A) receptor and to play an important role in the pathophysiology of depression and anxiety. During depression, the concentrations of 3α,5α-tetrahydroprogesterone and 3α,5β-tetrahydroprogesterone are decreased, while the levels of 3β,5α-tetrahydroprogesterone, a stereoisomer of 3α,5α-tetrahydroprogesterone, which may act as an antagonist for GABAergic steroids, are increased. Antidepressant drugs such as selective serotonin reuptake inhibitors (SSRIs) or mirtazapine apparently have an impact on key enzymes of neurosteroidogenesis and have been shown to normalize the disequilibrium of neuroactive steroids in depression by increasing 3α-reduced pregnane steroids and decreasing 3β,5α-tetrahydroprogesterone. Moreover, 3α-reduced neuroactive steroids have been demonstrated to possess antidepressant- and anxiolytic-like effects both in animal and human studies for themselves. In addition, the translacator protein (18 kDa) (TSPO), previously called peripheral benzodiazepine receptor, is the key element of the mitochondrial import machinery supplying the substrate cholesterol to the first steroidogenic enzyme (P450scc), which transforms cholesterol into pregnenolone, the precursor of all neurosteroids. TSPO ligands increase neurosteroidogenesis and are a target of novel anxiolytic drugs producing anxiolytic effects without causing the side effects normally associated with conventional benzodiazepines such as sedation or tolerance. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.

Neurosteroids as neuromodulators in the treatment of anxiety disorders

Anxiety disorders are the most common psychiatric disorders. They are frequently treated with benzodiazepines, which are fast acting highly effective anxiolytic agents. However, their long-term use is impaired by tolerance development and abuse liability. In contrast, antidepressants such as selective serotonin reuptake inhibitors (SSRIs) are considered as first-line treatment but have a slow onset of action. Neurosteroids are powerful allosteric modulators of GABA(A) and glutamate receptors. However, they also modulate sigma receptors and they are modulated themselves by SSRIs. Both pre-clinical and clinical studies have shown that neurosteroid homeostasis is altered in depression and anxiety disorders and antidepressants may act in part through restoring neurosteroid disbalance. Moreover, novel drugs interfering with neurosteroidogenesis such as ligands of the translocator protein (18 kDa) may represent an attractive pharmacological option for novel anxiolytics which lack the unwarranted side effects of benzodiazepines. Thus, neurosteroids are important endogenous neuromodulators for the physiology and pathophysiology of anxiety and they may constitute a novel therapeutic approach in the treatment of these disorders.

Neurosteroids' effects and mechanisms for social, cognitive, emotional, and physical functions

Hormones are trophic factors that integrate central and peripheral nervous system functions, and can influence social, cognitive, emotional and physical (SCEP) processes. Greater understanding of behavioral and neurobiological underpinnings of mental, cognitive, and/or physical changes with maturation is becoming increasingly important as the world's population ages. There are individual differences in how people age, but the factors that influence these differences are not well understood. Social supports are one factor that may influence the trajectory of age-related processes. The loss of close relationships, especially among older persons, is one of the greatest risk factors for mental and physical decline. Progesterone, secreted by the ovaries, or produced de novo in the brain, is readily converted centrally to 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), and can influence SCEP, through rapid, non-classical steroid-mediated actions. Our hypothesis is that 3alpha,5alpha-THP is a key trophic factor in SCEP and development. Our research has demonstrated that 3alpha,5alpha-THP facilitates social and sexual behavior of rodents, which evokes further increases in 3alpha,5alpha-THP in midbrain and hippocampus, brain areas involved in SCEP. The role of 3alpha,5alpha-THP to influence social and/or sexual experience, and thereby SCEP, is discussed in this review. Further understanding of these neurobiological and/or behavioral factors may lead to findings that ultimately can promote health and prevent disease.

The relevance of neuroactive steroids in schizophrenia, depression, and anxiety disorders

1. Neuroactive steroids are steroid hormones that exert rapid, nongenomic effects at ligand-gated ion channels. There is increasing awareness of the possible role of these steroids in the pathology and manifestation of symptoms of psychiatric disorders. The aim of this paper is to review the current knowledge of neuroactive steroid functioning in the central nervous system, and to assess the role of neuroactive steroids in the pathophysiology and treatment of symptoms of schizophrenia, depression, and anxiety disorders. Particular emphasis will be placed on GABAA receptor modulation, given the extensive knowledge of the interactions between this receptor complex, neuroactive steroids, and psychiatric illness. 2. A brief description of neuroactive steroid metabolism is followed by a discussion of the interactions of neuroactive steroids with acute and chronic stress and the HPA axis. Preclinical and clinical studies related to psychiatric disorders that have been conducted on neuroactive steroids are also described. 3. Plasma concentrations of some neuroactive steroids are altered in individuals suffering from schizophrenia, depression, or anxiety disorders compared to values in healthy controls. Some drugs used to treat these disorders have been reported to alter plasma and brain concentrations in clinical and preclinical studies, respectively. 4. Further research is warranted into the role of neuroactive steroids in the pathophysiology of psychiatric illnesses and the possible role of these steroids in the successful treatment of these disorders.

The complex roles of neurosteroids in depression and anxiety disorders

The role of neurosteroids in neuropsychiatric disorders has been thoroughly investigated in many research studies that have stressed their significant pathophysiological function in neuropsychiatry. In this review, we will focus mainly on the steroids active on the GABA(A) receptors studied in anxiety and depression. The aim is to discuss the controversial results reported in research on anxiety and depressive disorders. We suggest the combined use of biological parameters linked to psychopathological dimensions to make more homogeneous diagnoses and to develop more precise therapies for the treatment of depression and anxiety disorders. We discuss the role of neurosteroids in the pathophysiology and therapy of anxiety and depression. Finally, we consider the possibility of using quantification of mRNA expression of steroidogenic enzymes from peripheral sources in neuropsychiatry.

Neuroactive steroids and affective disorders

Neuroactive steroids modulate neurotransmission through modulation of specific neurotransmitter receptors such as gamma-aminobutyric acid type A (GABA(A)) receptors. Preclinical studies suggested that neuroactive steroids may modulate anxiety and depression-related behaviour and may contribute to the therapeutical effects of antidepressant drugs. Attenuations of such neuroactive steroids have been observed during major depression and in several anxiety disorders, suggesting a pathophysiological role in such psychiatric conditions. In panic disorder patients a dysequilibrium of neuroactive steroid composition has been observed, which may represent a counterregulatory mechanism against the occurrence of spontaneous panic attacks. Furthermore, alterations of 3alpha-reduced pregnane steroids during major depression were corrected by successful treatment with antidepressant drugs. However in contrast, non-pharmacological antidepressant treatment strategies did not affect neuroactive steroid composition. In addition, changes in neuroactive steroid concentrations after mirtazapine therapy occurred independently from the clinical response, thereby suggesting that changes in neuroactive steroid concentrations more likely reflect direct pharmacological effects of antidepressants rather than clinical improvement in general. Nevertheless, the effects of antidepressant pharmacotherapy on the composition of neuroactive steroids may contribute to the alleviation of certain depressive symptoms, such as amelioration of anxiety, inner tension or sleep disturbances. Moreover, first studies investigating the therapeutical effects of dehydroepiandrosterone revealed promising results in the treatment of major depression. In conclusion, neuroactive steroids are important endogenous modulators of depression and anxiety and may provide a basis for development of novel therapeutic agents in the treatment of affective disorders.

Neurosteroids, neuroactive steroids, and symptoms of affective disorders

Neurosteroids (NS) are steroids synthesized by the brain. Neuroactive steroids (NAS) refers to steroids that, independent of their origin, are capable of modifying neural activities. NAS bind and modulate different types of membrane receptors. The gamma amino butyric acid (GABA) and sigma receptor complexes have been the most extensively studied. Oxidized ring A reduced pregnanes, tetrahydroprogesterone (THP), and tetrahydrodeoxycorticosterone (THDOC) bind to the progesterone intracellular receptor (PR), and in this way can also regulate gene expression. Animal experimentation showed that salient symptoms of depression, viz., anxiety, sleep disturbances, and memory and sexual dysfunctions, are modulated by NAS. In turn, psychotropic drugs modulate NS and NAS levels. NS levels as well as NAS plasma concentrations change in patients with depression syndromes, the levels return to normal baseline with recovery, but normalization is not necessary for successful therapy. Results from current studies on the evolution of nervous systems, including evolutionary developmental biology as well as anatomical and physiological findings, almost preclude a categorical classification of the psychiatric ailments the human brain succumbs to. The persistence in maintaining such essentialist classifications may help to explain why up to now the search for biological markers in psychiatry has been an unrewarding effort. It is proposed that it would be more fruitful to focus on relationships between NAS and symptoms of psychiatric disorders, rather than with typologically defined disorders.

Neuroactive steroids as modulators of depression and anxiety

In addition to the well-known genomic effects of steroid molecules, certain neuroactive steroids control neurotransmission through the modulation of specific neurotransmitter receptors. Preclinical studies suggested that neuroactive steroids may modulate anxiety and depression-related behavior and may contribute to the therapeutic effects of antidepressant drugs. However, nonpharmacological antidepressant treatment strategies did not affect neuroactive steroid composition. These studies suggest that the changes in neuroactive steroids observed after antidepressant pharmacotherapy probably reflect distinct pharmacological properties of antidepressants, rather than the clinical response. Nevertheless, initial studies investigating the antidepressive effects of exogenously administered dehydroepiandosterone revealed promising results. In addition, in various anxiety disorders, alterations of neuroactive steroid levels have been observed. In conclusion, neuroactive steroids contribute to the pathophysiology of affective disorders and the mechanisms of action of antidepressants. They are important endogenous modulators of depression and anxiety and might offer new targets for the development of novel anxiolytic compounds.

Neuropsychopharmacological properties of neuroactive steroids in depression and anxiety disorders

Neuroactive steroids modulate neurotransmission through modulation of specific neurotransmitter receptors such as gamma-aminobutyric acid type A (GABAA) receptors. Preclinical studies suggested that neuroactive steroids may modulate anxiety- and depression-related behaviour and may contribute to the therapeutical effects of antidepressant drugs. Attenuations of 3alpha-reduced neuroactive steroids have been observed during major depression. This disequilibrium can be corrected by successful treatment with antidepressant drugs. However, non-pharmacological antidepressant treatment strategies did not affect neuroactive steroid composition independently from the clinical response. Further research is needed to clarify whether enhancement of neuroactive steroid levels might represent a new therapeutical approach in the treatment of affective disorders. Nevertheless, the first studies investigating the therapeutical effects of exogenously administered dehydroepiandosterone revealed promising results in the treatment of major depression. In addition, in various anxiety disorders alterations of neuroactive steroid levels have been observed. In panic disorder, in the absence of panic attacks, neuroactive steroid composition is opposite to that seen in depression, which may represent counter-regulatory mechanisms against the occurrence of spontaneous panic attacks. However, during experimentally induced panic attacks, there was a pronounced decline in GABAergic neuroactive steroids, which might contribute to the pathophysiology of panic attacks. In conclusion, neuroactive steroids contribute to the pathophysiology of affective disorders and the mechanisms of action of antidepressants. They are important endogenous modulators of depression and anxiety and may provide a basis for the development of novel therapeutic agents in the treatment of affective disorders.

The relevance of neurosteroids to clinical psychiatry: from the laboratory to the bedside

Neurosteroids are important neuroactive molecules with suggested central involvement in several neurophysiological and psychiatric disease processes. The discovery of neurosteroids followed the revelation that the brain exhibited the capacity to synthesize its own steroids in situ and thus be a potential site of steroidogenesis. In contrast to some steroids that exhibit traditional genomic steroid actions, most neurosteroids appear to regulate neuronal function by means of "non-genomic" mechanisms influencing neuronal excitability. Neurosteroids are synthesized either from CNS cholesterol or from peripheral steroid precursors and exhibit a wide range of modulatory effects on neurotransmitter receptor activity, most notably at the gamma-aminobutyric acid A (GABA(A)) receptor. Neurosteroids play an important role in neurodevelopment and neuroprotective effects, many aspects of which may have particular applicability to psychiatric disorders including various gender differences. Neurosteroids appear to be relevant to the pathophysiology and pharmacological treatment of many psychiatric disorders including the most notable mood and anxiety disorders, but also psychotic, childhood, eating, dementia, stress and postpartum disorders. It has been suggested that neurosteroids may become potential targets for pharmacological intervention in the future with further neurosteroid investigation contributing to a more comprehensive understanding of human behavior and psychopathology.

Plasma concentrations of anxiolytic neuroactive steroids in men with panic disorder

Plasma concentrations of neuroactive steroids in men with panic disorder (PD) were measured to evaluate their relations to psychopathology both before and during treatment. Participants comprised 13 men with PD and 10 normal controls. Patients were evaluated while drug-free as well as after 1 and 2 months of paroxetine therapy. Psychopathology was assessed by the State-Trait Anxiety Inventory (STAI), the Panic-Associated Symptom Scale, and the Fear Questionnaire total score. Plasma concentrations of steroids were measured by radioimmunoassay. The plasma concentrations of progesterone and dehydroepiandrosterone were greater in drug-free patients than in controls, whereas those of allopregnanolone and tetrahydrodeoxycorticosterone did not differ between the two groups. Paroxetine treatment for 2 months significantly increased the plasma concentration of allopregnanolone but did not affect those of the other steroids. At 2 months of therapy, allopregnanolone concentrations in patients were significantly greater than those in controls. The plasma concentrations of progesterone and tetrahydrodeoxycorticosterone correlated with the STAI state score in patients before treatment. Our data suggest that neuroactive steroids may play a role in PD in men.

Steroids, neuroactive steroids and neurosteroids in psychopathology

The term "neurosteroid" (NS) was introduced by Baulieu in 1981 to name a steroid hormone, dehydroepiandrosterone sulfate (DHEAS), that was found at high levels in the brain long after gonadectomy and adrenalectomy, and shown later to be synthetized by the brain. Later, androstenedione, pregnenolone and their sulfates and lipid derivatives as well as tetrahydrometabolites of progesterone (P) and deoxycorticosterone (DOC) were identified as neurosteroids. The term "neuroactive steroid" (NAS) refers to steroids which, independent of their origin, are capable of modifying neural activities. NASs bind and modulate different types of membrane receptors. The GABA and sigma receptor complexes have been the most extensively studied, while glycine-activated chloride channels, nicotinic acetylcholine receptors, voltage-activated calcium channels, although less explored, are also modulated by NASs. Within the glutamate receptor family, N-methyl-d-aspartate (NMDA) receptors, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and kainate receptors have also been demonstrated to be a target for steroid modulation. Besides their membrane effects, once inside the neuron oxidation of Ring A reduced pregnanes, THP and THDOC, bind to the progesterone intracellular receptor and regulate gene expression through this path. The involvement of NASs on depression syndromes, anxiety disorders, stress responses to different stress stimuli, memory processes and related phenomena such as long-term potentiation are reviewed and critically evaluated. The importance of context for the interpretation of behavioral effects of hormones as well as for hormonal levels in body fluids is emphasized. Some suggestions for further research are given.

Plasma concentrations of anxiolytic neurosteroids in men with normal anxiety scores: a correlation analysis

Neurosteroids are physiological regulators of anxiety in experimental animals, but there are no data for humans about the modulatory effects of the hormones on normal aspects of this emotional parameter. Plasma concentrations of four neurosteroids, pregnenolone, progesterone (PROG), allopregnanolone and tetrahydrodeoxycorticosterone, suggested to be major anxiety regulators in experimental animals, were measured in a group of 58 physically and psychologically normal adult male subjects. In parallel, trait (genotypical) and state (phenotypical) anxiety scores were measured by the State-Trait Anxiety Inventory. The possible correlations between the hormonal secretions and the psychological parameters were statistically analyzed. The neurosteroid concentrations and the anxiety scores of the probands were within the ranges of normality according to data of the literature and our own. PROG concentrations correlated significantly with state anxiety scores. These data suggest that neurosteroids may physiologically modulate anxiety not only in experimental animals but also in humans.

Neurosteroids and neuroactive drugs in mental disorders

Clinical and preclinical studies have suggested that fluctuations in the peripheral and brain concentrations of progesterone and deoxycorticosterone and its metabolites 3alpha,5alpha-tetrahydroprogesterone and 3alpha,5alpha-tetrahydrodeoxycorticosterone, respectively, might play an important role in certain pathological conditions characterized by emotional or affective disturbances, including major depression, anxiety disorders, and schizophrenia. Moreover, it has been shown that administration of drugs having clinical relevance in the treatment of these pathologies influence the secretion of these steroids. It remains to be determined, however, whether such changes in the concentrations of neuroactive steroids are a cause of, a risk factor for, or a consequence of mental disorders. The observation that effective pharmacological treatment of some of these pathologies influences the concentrations of neuroactive steroids suggests that these endogenous compounds might themselves prove to be efficacious in the treatment of mental illness.

Neurosteroid secretion in panic disorder

Evidence that neurosteroids have anxiolytic effects in animal models of anxiety has suggested that alterations of neurosteroid secretion might be implicated in the pathogenetic mechanisms of anxiety disorders in humans. In 25 female patients with panic disorder (PD) and 11 healthy female controls, we measured plasma concentrations of progesterone (PROG), pregnenolone (PREG), allopregnanolone (3alpha,5alpha-tetrahydroprogesterone=3alpha,5alpha-THPROG), dehydroepiandrosterone (DHEA) and tetrahydrodeoxycorticosterone (3alpha,5alpha-THDOC) during a drug-free month and during the following month of paroxetine therapy. The neurosteroids were measured during the early follicular phase, the mid-luteal phase and the premenstrual phase of both months (days 7, 22 and 27 from the beginning of the cycle). Significantly higher levels in patients than controls were found in PROG during the mid-luteal phase of both months, PREG in the premenstrual phase in the drug-free month, 3alpha,5alpha-THPROG during the follicular phase of the drug-free month and during the premenstrual phase of the therapy month, and 3alpha,5alpha-THDOC during the premenstrual phases of both months. DHEA levels did not differ in patients and controls. These results suggest that neurosteroids in PD are hypersecreted, possibly as an attempt to counteract the anxiogenic underlying hyperactivity of the hypothalamo-pituitary-adrenal axis and to improve a reduced GABA(A) receptor sensitivity.