GABAA receptor-acting neurosteroids: a role in the development and regulation of the stress response.

Regulation of hypothalamic-pituitary-adrenocortical (HPA) axis activity by stress is a fundamental survival mechanism and HPA-dysfunction is implicated in psychiatric disorders. Adverse early life experiences, e.g. poor maternal care, negatively influence brain development and programs an abnormal stress response by encoding long-lasting molecular changes, which may extend to the next generation. How HPA-dysfunction leads to the development of affective disorders is complex, but may involve GABAA receptors (GABAARs), as they curtail stress-induced HPA axis activation. Of particular interest are endogenous neurosteroids that potently modulate the function of GABAARs and exhibit stress-protective properties. Importantly, neurosteroid levels rise rapidly during acute stress, are perturbed in chronic stress and are implicated in the behavioural changes associated with early-life adversity. We will appraise how GABAAR-active neurosteroids may impact on HPA axis development and the orchestration of the stress-evoked response. The significance of these actions will be discussed in the context of stress-associated mood disorders.

Dysfunctional astrocytic and synaptic regulation of hypothalamic glutamatergic transmission in a mouse model of early-life adversity: relevance to neurosteroids and programming of the stress response.

Adverse early-life experiences, such as poor maternal care, program an abnormal stress response that may involve an altered balance between excitatory and inhibitory signals. Here, we explored how early-life stress (ELS) affects excitatory and inhibitory transmission in corticotrophin-releasing factor (CRF)-expressing dorsal-medial (mpd) neurons of the neonatal mouse hypothalamus. We report that ELS associates with enhanced excitatory glutamatergic transmission that is manifested as an increased frequency of synaptic events and increased extrasynaptic conductance, with the latter associated with dysfunctional astrocytic regulation of glutamate levels. The neurosteroid 5α-pregnan-3α-ol-20-one (5α3α-THPROG) is an endogenous, positive modulator of GABAA receptors (GABAARs) that is abundant during brain development and rises rapidly during acute stress, thereby enhancing inhibition to curtail stress-induced activation of the hypothalamic-pituitary-adrenocortical axis. In control mpd neurons, 5α3α-THPROG potently suppressed neuronal discharge, but this action was greatly compromised by prior ELS exposure. This neurosteroid insensitivity did not primarily result from perturbations of GABAergic inhibition, but rather arose functionally from the increased excitatory drive onto mpd neurons. Previous reports indicated that mice (dams) lacking the GABAAR δ subunit (δ(0/0)) exhibit altered maternal behavior. Intriguingly, δ(0/0) offspring showed some hallmarks of abnormal maternal care that were further exacerbated by ELS. Moreover, in common with ELS, mpd neurons of δ(0/0) pups exhibited increased synaptic and extrasynaptic glutamatergic transmission and consequently a blunted neurosteroid suppression of neuronal firing. This study reveals that increased synaptic and tonic glutamatergic transmission may be a common maladaptation to ELS, leading to enhanced excitation of CRF-releasing neurons, and identifies neurosteroids as putative early regulators of the stress neurocircuitry.

The influence of demand characteristics and social desirability on clients' ratings of the therapeutic alliance.

OBJECTIVE: To examine demand characteristics, social desirability on clients' rating of working alliance using the Session Rating Scale (SRS; Miller, Duncan, & Johnson, 2000). METHOD: Clients (N = 102) at two sites were randomly assigned to one of three alliance feedback conditions: (a) IF--SRS completed in presence of therapist and the results discussed immediately afterward; (b) Next Session Feedback--SRS completed alone and results discussed next session; or (c) No Feedback--SRS completed alone and results not available to therapist. Clients completed the SRS for the first three sessions of treatment. RESULTS: No statistically significant differences in SRS scores across the feedback conditions were found. Additionally, the analysis showed that SRS scores were not correlated with a measure of social desirability but were correlated with an established alliance measure. CONCLUSIONS: The results indicate that alliance scores were not inflated due to the presence of a therapist or knowing that the scores would be observed by the therapist.

Polymeric nanoparticles for sustained down-regulation of annexin A2 inhibit prostate tumor growth.

Prostate cancer is the most frequently diagnosed cancer and the second leading cause of cancer related death in Western men. In prostate intraepithelial neoplasia annexin A2 expression is absent however upon loss of androgen dependence annexin A2 is subsequently over-expressed. Regaining regulatory control of annexin A2 presents a means of therapy in the treatment of hormone refractory prostate cancers. In an effort to regain control of aberrant annexin A2 expression we have formulated poly lactide-co-glycolide (PLGA) nanoparticles loaded with pDrive-sh AnxA2 plasmid DNA. These nanoparticles are capable of sustained intracellular delivery of pDrive-sh AnxA2 plasmid DNA vector for long-term siRNA mediated down-regulation of annexin A2. Intra-tumoral administration of pDrive-sh AnxA2 loaded nanoparticles to xenograft prostate tumors in nude mice demonstrates an overall decrease in tumor growth. The decrease in tumor growth is through a reduction of annexin A2 and VEGF mRNA and protein levels within the tumor mass. Administration of blank nanoparticles demonstrated no alteration in tumor growth or annexin A2 and VEGF at either the mRNA or protein levels. Our findings suggest that the use of sustained-release polymeric nanoparticles for down-regulation of annexin A2 expression may serve as an effective adjuvant treatment option for prostate cancer.

Door openings in the operating room are associated with increased environmental contamination.

Door openings in the operating room (OR) have been hypothesized to increase OR environmental contamination. This study measured average colony-forming units (CFU) in the OR as a function of door openings and other potentially important variables. Bacterial settle plates were placed inside and outside of laminar airflow (LAF) by both exit doors, on the instrument table, and on the back instrument table (if applicable) for 48 orthopedic and general surgery procedures. CFU data were paired to Staphylococcus aureus colonization status, door openings, surgery duration, time of day, OR location, number of staff, use of warming devices, temperature, and humidity. The number of door openings in the OR and surgery duration were significantly associated with increased CFU in the OR overall and outside of LAF. However, under LAF conditions, only the number of OR personnel was significantly associated with increased CFU.

Early-life adversity selectively impairs α2-GABAA receptor expression in the mouse nucleus accumbens and influences the behavioral effects of cocaine.

Haplotypes of the Gabra2 gene encoding the α2-subunit of the GABAA receptor (GABAAR) are associated with drug abuse, suggesting that α2-GABAARs may play an important role in the circuitry underlying drug misuse. The genetic association of Gabra2 haplotypes with cocaine addiction appears to be evident primarily in individuals who had experienced childhood trauma. Given this association of childhood trauma, cocaine abuse and the Gabra2 haplotypes, we have explored in a mouse model of early life adversity (ELA) whether such events influence the behavioral effects of cocaine and if, as suggested by the human studies, α2-GABAARs in the nucleus accumbens (NAc) are involved in these perturbed behaviors. In adult mice prior ELA caused a selective decrease of accumbal α2-subunit mRNA, resulting in a selective decrease in the number and size of the α2-subunit (but not the α1-subunit) immunoreactive clusters in NAc core medium spiny neurons (MSNs). Functionally, in adult MSNs ELA decreased the amplitude and frequency of GABAAR-mediated miniature inhibitory postsynaptic currents (mIPSCs), a profile similar to that of α2 "knock-out" (α2-/-) mice. Behaviourally, adult male ELA and α2-/- mice exhibited an enhanced locomotor response to acute cocaine and blunted sensitisation upon repeated cocaine administration, when compared to their appropriate controls. Collectively, these findings reveal a neurobiological mechanism which may relate to the clinical observation that early trauma increases the risk for substance abuse disorder (SAD) in individuals harbouring haplotypic variations in the Gabra2 gene.