Immunization with a heat-killed preparation of Mycobacterium vaccae NCTC 11659 enhances auditory-cued fear extinction in a stress-dependent manner.

Stress-related psychiatric disorders including anxiety disorders, mood disorders, and trauma and stressor-related disorders, such as posttraumatic stress disorder (PTSD), affect millions of people world-wide each year. Individuals with stress-related psychiatric disorders have been found to have poor immunoregulation, increased proinflammatory markers, and dysregulation of fear memory. The "Old Friends" hypothesis proposes that a lack of immunoregulatory inputs has led to a higher prevalence of inflammatory disorders and stress-related psychiatric disorders, in which inappropriate inflammation is thought to be a risk factor.

Effects of Immunization With the Soil-Derived Bacterium on Stress Coping Behaviors and Cognitive Performance in a "Two Hit" Stressor Model.

Previous studies demonstrate that NCTC 11659 (), a soil-derived bacterium with anti-inflammatory and immunoregulatory properties, is a potentially useful countermeasure against negative outcomes to stressors. Here we used male C57BL/6NCrl mice to determine if repeated immunization with is an effective countermeasure in a "two hit" stress exposure model of chronic disruption of rhythms (CDR) followed by acute social defeat (SD). On day -28, mice received implants of biotelemetric recording devices to monitor 24-h rhythms of locomotor activity.

Effects of maternal separation on serotonergic systems in the dorsal and median raphe nuclei of adult male Tph2-deficient mice.

Previous studies have highlighted interactions between serotonergic systems and adverse early life experience as important gene x environment determinants of risk of stress-related psychiatric disorders. Evidence suggests that mice deficient in Tph2, the rate-limiting enzyme for brain serotonin synthesis, display disruptions in behavioral phenotypes relevant to stress-related psychiatric disorders. The aim of this study was to determine how maternal separation in wild-type, heterozygous, and Tph2 knockout mice affects mRNA expression of serotonin-related genes.

Treatment with a heat-killed preparation of Mycobacterium vaccae after fear conditioning enhances fear extinction in the fear-potentiated startle paradigm.

The hygiene hypothesis or "Old Friends" hypothesis proposes that inflammatory diseases are increasing in modern urban societies, due in part to reduced exposure to microorganisms that drive immunoregulatory circuits and a failure to terminate inappropriate inflammatory responses. Inappropriate inflammation is also emerging as a risk factor for anxiety disorders, affective disorders, and trauma-and stressor-related disorders, including posttraumatic stress disorder (PTSD), which is characterized as persistent re-experiencing of the trauma after a traumatic experience. Traumatic experiences can lead to long-lasting fear memories and fear potentiation of the acoustic startle reflex.

Local inhibition of uptake transporters augments stress-induced increases in serotonin in the rat central amygdala.

Organic cation transporter 3 (OCT3) is a corticosterone-sensitive, low-affinity, high-capacity transporter. This transporter functions, in part, to clear monoamines, including serotonin (5-HT), from the extracellular space. The central nucleus of the amygdala (CeA) is an important structure controlling fear- and anxiety-related behaviors.