Platelet imipramine binding in patients with posttraumatic stress disorder before and after phenelzine treatment

Alterations in stress reactivity after long-term treatment with paroxetine in women with posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is typically accompanied by both acute and chronic alterations in the stress response. These alterations have mostly been described in individuals under baseline conditions, but studies have also used a challenge model to assess the role of the hypothalamic-pituitary-adrenal (HPA) axis in the stress response. The purpose of this article was to assess the effect of long-term treatment with the selective reuptake inhibitor (SSRI), paroxetine, on stress reactivity in patients with PTSD. We assessed diurnal salivary cortisol and urinary cortisol as well as cortisol, heart rate, and behavioral responses to a standardized cognitive stress challenge, in 13 female patients with chronic PTSD before and after 12 months of paroxetine treatment. Treatment resulted in a significant decrease in PTSD symptoms. Twenty-four-hour urinary cortisol was lower compared to base line after successful treatment. Treatment resulted in a decrease of salivary cortisol levels on all time points on a diurnal curve. Despite similar stress perception, cortisol response to the cognitive stress challenge resulted in a 26.5% relative decrease in stress-induced salivary cortisol with treatment. These results suggest that successful treatment with SSRI in chronic PTSD is associated with a trend for a decrease in baseline diurnal cortisol and with reduced cortisol reactivity to stress.

Role of the orbital cortex and of the serotonergic system in a rat model of obsessive compulsive disorder

The serotonergic system and the orbitofrontal cortex have been consistently implicated in the pathophysiology of obsessive compulsive disorder. Yet, the relations between these two systems and the ways they interact in producing obsessions and compulsions are poorly understood. The present study tested the hypothesis that pathology of the orbitofrontal cortex leads to a dysregulation of the serotonergic system which is manifested in compulsive behavior, using a new rat model of this disorder. In the model, 'compulsive' behavior is induced by attenuating a signal indicating that a lever-press response was effective in producing food. We found that lesion to the rat orbital cortex led to a selective increase in compulsive lever-pressing that was prevented by the serotonin re-uptake inhibitor, paroxetine, and was paralleled by an increase in the density of the striatal serotonin transporter, assessed using high affinity [3H]imipramine binding. These results suggest that the serotonergic system is involved in orbital lesion-induced compulsivity, and provide a possible account for the observed association between obsessions and compulsions and dysfunction of the orbitofrontal cortex and of the serotonergic system in obsessive compulsive disorder.

Glucocorticoid-regulated human serotonin transporter (5-HTT) expression is modulated by the 5-HTT gene-promotor-linked polymorphic region

Mood, emotion and cognition are modulated by serotonergic neurotransmission, while the physiological function of serotonergic synapses depends on serotonin reuptake, which is mediated by the serotonin transporter (5-HTT). Allelic variation of 5-HTT expression in humans is caused by a functional gene-promoter polymorphism with two predominant variant alleles, which are associated with variations in anxiety measures as previously reported. Here we report that administration of dexamethasone, a potent glucocorticosteroid hormone, results in an increase in 5-HTT expression in immortalized human B-lymphoblastoid cells, which express the human 5-HTT. Functional reporter gene assays as well as 5-HT uptake and inhibitor binding measures revealed a genotype-dependent dose-response to glucocorticosteroid administration, which was antagonized by RU 38486, a non-specific glucocorticosteroid hormone antagonist. The allele-specific differences after administration of dexamethasone depended on the repetitive GC-rich sequence located approximately 1.4 kb upstream of the 5-HTT gene transcription site because of absence of a significant steroid effect after transfecting a deletional mutant reporter gene construct, which lacks this repetitive promoter sequence. Our findings may contribute to explain the vulnerability to stress-related disorders in susceptible individuals, in whom further clinical studies should follow up on these in vitro findings.

Platelet 5-HT concentration and comorbid depression in war veterans with and without posttraumatic stress disorder

BACKGROUND

The serotonergic system is implicated in the pathophysiology of posttraumatic stress disorder (PTSD) and depression. The present study focused on platelet serotonin (5-HT) concentration and symptoms of comorbid depression in war veterans with or without PTSD.

METHODS

PTSD and depression were evaluated using Clinician Administered PTSD Scale, Davidson Trauma Scale, Montgomery-Asberg Depression Rating Scale and Hamilton Anxiety Scale. Sixty-five male drug-free war veterans (48 with PTSD and 17 without PTSD) and 65 age- and sex-matched healthy controls were studied.

RESULTS

Comorbid depression occurred in 54 and 31% of war veterans with PTSD and without PTSD, respectively. Platelet 5-HT concentration was similar in the groups of depressed and nondepressed war veterans with or without PTSD and healthy controls. Platelet 5-HT concentration was found to differ between war veterans with various degrees of appetite loss. A positive correlation was observed between platelet 5-HT concentration and severity of appetite loss in veterans with PTSD. There was no relationship between platelet 5-HT concentration and severity of other symptoms of PTSD or depression.

LIMITATIONS

War veterans included in the study were outpatients.

CONCLUSIONS

War veterans with PTSD had a high incidence of comorbid depression, that was not related to platelet 5-HT concentration. The marked relationship between platelet 5-HT concentration and severity of appetite loss, suggested that 5-HT system is involved in the regulation of appetite, at least in depressed war veterans with PTSD.

Circuits and systems in stress. II. Applications to neurobiology and treatment in posttraumatic stress disorder

This paper follows the preclinical work on the effects of stress on neurobiological and neuroendocrine systems and provides a comprehensive working model for understanding the pathophysiology of posttraumatic stress disorder (PTSD). Studies of the neurobiology of PTSD in clinical populations are reviewed. Specific brain areas that play an important role in a variety of types of memory are also preferentially affected by stress, including hippocampus, amygdala, medial prefrontal cortex, and cingulate. This review indicates the involvement of these brain systems in the stress response, and in learning and memory. Affected systems in the neural circuitry of PTSD are reviewed (hypothalamic-pituitary-adrenal axis (HPA-axis), catecholaminergic and serotonergic systems, endogenous benzodiazepines, neuropeptides, hypothalamic-pituitary-thyroid axis (HPT-axis), and neuro-immunological alterations) as well as changes found with structural and functional neuroimaging methods. Converging evidence has emphasized the role of early-life trauma in the development of PTSD and other trauma-related disorders. Current and new targets for systems that play a role in the neural circuitry of PTSD are discussed. This material provides a basis for understanding the psychopathology of stress-related disorders, in particular PTSD.

Pharmacology for post-traumatic stress disorder related to childhood sexual abuse: a literature review

TOPIC

Post-traumatic stress disorder (PTSD) related to pharmacotherapy responses in general and specifically to noncombat symptomatology related to childhood sexual abuse.

PURPOSE

To explore findings related to pharmacological advances in the treatment of PTSD and relate the findings to the treatment of childhood sexual abuse.

SOURCES

Published literature.

CONCLUSIONS

The literature on pharmacotherapy for PTSD in general and childhood trauma and PTSD in particular is small and inconsistent, but we need to be aware of any and all advances.

Posttraumatic stress disorder and platelet serotonin measures

The role of serotonin (5HT) in the pathophysiology of posttraumatic stress disorder (PTSD) has been suggested by the overlap in clinical symptoms between PTSD and psychiatric conditions in which a serotonin dysfunction is implicated, as well as by the therapeutic efficiency of 5HT-related drugs (antidepressants, selective serotonin reuptake inhibitors and monoamine oxidase inhibitors) in alleviating symptoms in PTSD. In the present study, the blood platelet, which has been proposed as a peripheral model for the central serotonergic neurons, has been used to search for alterations in 5HT mechanisms in PTSD. Platelet serotonin level and kinetics of serotonin transporter and monoamine oxidase (MAO-B) were assessed in 63 combat-related PTSD patients and 43 sex and age-matched control subjects. A significant reduction in maximal velocity of platelet MAO-B (approx. 30%), with no changes in the enzyme affinity was observed in our patient sample. Conversely, no alterations in kinetic parameters (V(max), K(m)) of platelet serotonin transporter, as well as in platelet 5HT level, were found in the PTSD group.

Low platelet-poor plasma concentrations of serotonin in patients with combat-related posttraumatic stress disorder

BACKGROUND

Combat-related posttraumatic stress disorder (CR-PTSD) is associated with a dysregulation of various neurotransmitter systems.

METHODS

We assessed levels of platelet-poor plasma (PPP) norepinephrine (NE), and serotonin (5-HT), and 24-hour urinary excretion of NE, dopamine (DA), and homovanillic acid (HVA) in 17 male outpatients with untreated chronic CR-PTSD (age, 33.1 +/- 7.4 years) and 10 normal control subjects (age, 35.8 +/- 2.7 years).

RESULTS

Compared with the control subjects, the PTSD patients showed significantly lower PPP 5-HT levels, elevated PPP NE levels, and significantly higher mean 24-hour urinary excretion of all three catecholamines (NE, DA, and HVA). The 24-hour urinary HVA values of the CR-PTSD patients correlated significantly and positively with the total Impact of Event Scale scores and the avoidance symptoms cluster scores, and the PPP 5-HT levels correlated negatively with the Hamilton Anxiety Rating Scale scores. The PPP NE/5-HT ratio was significantly higher in the study group than in the control subjects.

CONCLUSIONS

We believe this combined enhanced noradrenergic activity and diminished 5-HT activity may be relevant to the neurobiology of CR-PTSD.

Platelet paroxetine binding in post-traumatic stress disorder

Sixty-two subjects, 45 with post-traumatic stress disorder (PTSD) and 17 healthy control subjects, were examined in a study of serotonin function measured by [3H]paroxetine binding to platelet membranes. Subjects were selected from male combat exposed veterans. The mean (+/- S.D.) Kd was 0.078 +/- 0.045 nM for the PTSD patient group and 0.064 +/- 0.037 nM for the control group. The mean Bmax was 934 + 238 fmol/mg protein for the PTSD patient group and 1011 +/- 363 fmol/mg protein for the control group. There was no significant difference between the groups for either Kd or Bmax before or after controlling for season of sampling. There were no significant differences between subjects with current PTSD and those with PTSD in the past, or between PTSD subjects with or without concurrent major depressive disorder. This study finds no relationship between PTSD, major depressive disorder and peripheral serotonin function measured by [3H]paroxetine binding to blood platelets.