Noradrenergic receptor sensitivity in obsessive-compulsive disorders: I. Growth hormone response to clonidine stimulation

The development of compulsive coping behaviour is associated with a downregulation of Arc in a Locus Coeruleus neuronal ensemble

Some compulsive disorders have been considered to stem from the loss of control over coping strategies, such as displacement. However, the cellular mechanisms involved in the acquisition of coping behaviours and their subsequent compulsive manifestation in vulnerable individuals have not been elucidated. Considering the role of the locus coeruleus (LC) noradrenaline-dependent system in stress and related excessive behaviours, we hypothesised that neuroplastic changes in the LC may be associated with the acquisition of an adjunctive polydipsic water drinking, a prototypical displacement behaviour, and the ensuing development of compulsion in vulnerable individuals. Thus, male Sprague Dawley rats were characterised for their tendency, or not, to develop compulsive polydipsic drinking in a schedule-induced polydipsia (SIP) procedure before their fresh brains were harvested. A new quantification tool for RNAscope assays revealed that the development of compulsive adjunctive behaviour was associated with a low mRNA copy number of the plasticity marker Arc in the LC which appeared to be driven by specific adaptations in an ensemble of tyrosine hydroxylase (TH)+, zif268- neurons. This ensemble was specifically engaged by the expression of compulsive adjunctive behaviour, not by stress, because its functional recruitment was not observed in individuals that no longer had access to the water bottle before sacrifice, while it consistently correlated with the levels of polydipsic water drinking only when it had become compulsive. Together these findings suggest that downregulation of Arc mRNA levels in a population of a TH+/zif268- LC neurons represents a signature of the tendency to develop compulsive coping behaviours.

The Use of Clonidine in the Treatment of Debilitating Obsessive-Compulsive Behaviors Comorbid With Depression and Post-Traumatic Stress Disorder: A Case Report

Clonidine is an alpha-2 agonist traditionally used as an antihypertensive, and more recently in the treatment of psychiatric disorders such as attention-deficit hyperactive disorder (ADHD), tic disorders such as Tourette’s syndrome, and post-traumatic stress disorder (PTSD). However, there are scarce data in the literature about the use of clonidine in the treatment of obsessive-compulsive disorder (OCD).

In this report, we present the case of a 16-year-old female suffering from OCD. The first-line treatment with sertraline was not very efficacious in improving her symptoms and even led to worsening of the same. However, subsequent treatment with clonidine resulted in rapid and significant improvement in her condition. We postulate that further research is required to gain more insight into the therapeutic potential of clonidine in OCD patients.

Obsessive-compulsive disorder and growth factors: A comparative review

The goal of this article is to clarify the role of various growth factors in the establishment and progression of obsessive-compulsive disorder (OCD). OCD is a chronic mental disorder with recurrent intrusive thoughts and/or repetitive compulsive behaviors that increase during stressful periods. Growth and neurotrophic factors may be contributing factors in the pathophysiology of OCD. Many of them are synthesized and released within the central nervous system and act as trophic agents in neurons; some of them are involved in brain growth, development, neurogenesis, myelination and plasticity, while others take part in the protection of the nervous system following brain injuries. This paper attempts to identify all articles investigating the relationship between OCD and neurotrophic and growth factors, in both animal and human studies, with a focus on adult brain studies. Based on the PubMed and Scopus and Science Direct search tools, the available articles and studies are reviewed. Out of 230 records in total, the ones related to our review topic were taken into account to further understand the pathophysiological mechanism(s) of OCD, providing methods to improve its symptoms via the modification of neurotrophins and growth factor imbalances.

Emotional interference modulates performance monitoring in patients with obsessive-compulsive disorder

BACKGROUND

Enhanced performance monitoring in patients with obsessive-compulsive disorder (OCD), typically measured by error-related negativity (ERN), provides evidence for the fronto-striatal model of OCD. Here, we examined whether performance monitoring in OCD patients is modulated by emotional interference induced by task-irrelevant emotional stimuli.

METHODS

A modified version of the flanker task with emotional face stimuli (fearful vs. neutral faces) was performed by 22 OCD patients and 22 healthy control subjects while electroencephalogram signals were recorded. Response-locked ERN was defined as the mean amplitude from 20 to 120msec after the response.

RESULTS

During trials with fearful face stimuli, OCD patients showed larger ERN amplitude than control subjects, but there was no difference between groups during trials with neutral face stimuli. Whereas OCD patients exhibited enhanced ERN amplitude in the fearful face condition compared with the neutral face condition, control subjects showed no variation between conditions. OCD patients also exhibited larger correct response negativity amplitude than control subjects in both fearful and neutral face conditions.

CONCLUSIONS

These results support the theory that OCD involves overactive performance monitoring and indicate that emotional interference modulates performance monitoring in patients with OCD, thus implying that affective function in the fronto-striatal network forms part of the neural basis of OCD.

Growth hormone response to growth hormone-releasing hormone stimulation in obsessive-compulsive disorder

Two groups of 30 patients with obsessive-compulsive disorder and 30 age- and sex-matched healthy control subjects were given a growth hormone-releasing hormone (GHRH) stimulation test to determine: (1) whether the downstream function of the somatotropic axis (growth hormone = GH, somatomedin-C = SMD-C) was impaired; (2) what might be the central alteration responsible for such impairment; and (3) whether alterations might be linked to the etiopathogenesis of the disease. Basal values of GH and SMD-C were the same in patients and control subjects, but GH responses to GHRH stimulation were significantly lower in patients than in control subjects. The absence of a pathology of basal GH and SMD-C concentrations indicates that the blunted GH responses to GHRH stimulation are not due to a negative feedback mechanism and suggests that a central neurotransmitter-neuropeptide pathology might be involved in the phenomenon.

Clonidine challenge in childhood anxiety disorder

OBJECTIVE

To evaluate the neurohormonal and subjective mood response of children with anxiety disorder to clonidine challenge

METHOD

Children with DSM-IV diagnoses of anxiety disorder (ANX) (n = 24) and normal controls (n = 15) were given a challenge of intravenous clonidine (1.3 micrograms/kg) and provided neurohormonal and mood self-report assessment over a 180-minute period.

RESULTS

The ANX group differed from normal controls in Hamilton Anxiety Rating, Revised Children's Manifest Anxiety Scale score, and maximum change from baseline (delta max) in growth hormone (GH). Clonidine-stimulated GH concentration of the ANX group was significantly elevated compared with that of controls but returned to baseline within 2 hours. A subgroup with obsessive-compulsive disorder (OCD) (n = 9) had significantly higher delta max GH (17.5 +/- 10.1 ng/mL) than the group with other anxiety disorders (ANX-OCD) (9.1 +/- 5.8 ng/mL) and controls (5.7 +/- 4.1 ng/mL).

CONCLUSION

GH response to clonidine challenge is not blunted in ANX subjects. This finding is in contrast to adult disorder and suggests that adrenergic postsynaptic receptor down-regulation is not a feature of childhood anxiety. These findings suggest enhanced central adrenergic sensitivity in ANX which is most pronounced in OCD and argue against a neurobiological continuum from childhood to adult anxiety disorder.

Plasma interleukin-1 beta and tumor necrosis factor concentrations in obsessive-compulsive disorders

Plasma interleukin-1 beta (Il-1 beta) and tumor necrosis factor-alpha (TNF-alpha) concentrations were measured twice, at a 48-hour interval, in 27 drug-free obsessive-compulsive patients (12 women and 15 men) and in 27 sex-age-matched healthy controls. Il-1 beta and TNF-alpha concentrations were significantly lower in patients than in controls, whereas there were no differences in either group between men and women, between the samples of the two days, or, in the patients, between those who had and those who had not been previously treated with psychopharmacologic drugs.

Noradrenergic receptor sensitivity in obsessive compulsive disorder: II. Cortisol response to acute clonidine administration

Sensitivity of pre-synaptic alpha-2- and post-synaptic alpha-1- and beta-adrenoceptors was investigated in 15 patients with obsessive-compulsive disorder (OCD) and in 15 age- and sex-matched healthy controls, by measuring cortisol responses to saline administration and to inhibition by clonidine (clon), a noradrenergic receptor agonist. Basal values of cortisol and responses to administration of saline and of clon were the same in patients and controls.