Expression of c-Fos following voluntary ingestion of a novel or familiar taste in rats.

Taste neophobia, the rejection of novel tastes or foods, involves an interplay of various brain regions encompassing areas within the central gustatory system, as well as nuclei serving other functions. Previous findings, utilising c-Fos imaging, identified several brain regions which displayed higher activity after ingestion of a novel taste as compared to a familiar taste. The present study extends this analysis to include additional regions suspected of contributing to the neurocircuitry involved in evoking taste neophobia. Our data show increased c-Fos expression in the basolateral amygdala, central nucleus of the amygdala, gustatory portion of the thalamus, gustatory portion of the insular cortex and the medial and lateral regions of the parabrachial nucleus. These results confirm the contribution of areas previously identified as active during ingestion of novel tastes and expose additional areas that express elevated levels of c-Fos under these conditions, thus adding to the neural network involved in the detection and initial processing of taste novelty.

Angiotensin II Type 2 Receptor-Expressing Neurons in the Central Amygdala Influence Fear-Related Behavior.

BACKGROUND: The renin-angiotensin system has been implicated in posttraumatic stress disorder; however, the mechanisms responsible for this connection and the therapeutic potential of targeting the renin-angiotensin system in posttraumatic stress disorder remain unknown. Using an angiotensin receptor bacterial artificial chromosome (BAC) and enhanced green fluorescent protein (eGFP) reporter mouse, combined with neuroanatomical, pharmacological, and behavioral approaches, we examined the role of angiotensin II type 2 receptor (AT2R) in fear-related behavior. METHODS: Dual immunohistochemistry with retrograde labeling was used to characterize AT2R-eGFP+ cells in the amygdala of the AT2R-eGFP-BAC reporter mouse. Pavlovian fear conditioning and behavioral pharmacological analyses were used to demonstrate the effects of AT2R activation on fear memory in male C57BL/6 mice. RESULTS: AT2R-eGFP+ neurons in the amygdala were predominantly expressed in the medial amygdala and the medial division of the central amygdala (CeM), with little AT2R-eGFP expression in the basolateral amygdala or lateral division of the central amygdala. Characterization of AT2R-eGFP+ neurons in the CeM demonstrated distinct localization to gamma-aminobutyric acidergic projection neurons. Mice receiving acute intra-central amygdala injections of the selective AT2R agonist compound 21 prior to tests for cued or contextual fear expression displayed less freezing. Retrograde labeling of AT2R-eGFP+ neurons projecting to the periaqueductal gray revealed AT2R-eGFP+ neuronal projections from the CeM to the periaqueductal gray, a key brain structure mediating fear-related freezing. CONCLUSIONS: These findings suggest that CeM AT2R-expressing neurons can modulate central amygdala outputs that play a role in fear expression, providing new evidence for a novel angiotensinergic circuit in the regulation of fear.

The modification of the ketogenic diet mitigates its stunting effects in rodents.

The high-fat and low-carbohydrate ketogenic diet (HFKD) is extensively studied within the fields of numerous diseases, including cancer and neurological disorders. Since most studies incorporate animal models, ensuring the quality of ketogenic rodent diets is important, both in the context of laboratory animal welfare as well as for the accuracy of the obtained results. In this study we implemented a modification to a commonly used ketogenic rodent chow by replacing non-resorbable cellulose with wheat bran. We assessed the effects of month-long treatment with either the unmodified or the modified HFKD on the growth and development of young male rats. Daily body weight, functional performance, and brain morphometric parameters were assessed to evaluate the influence of both applied diets on rodent development. Our results revealed that the unmodified ketogenic chow induced strong side effects that included weakness, emaciation, and brain undergrowth concomitant to growth inhibition. However, application of the ketogenic chow supplemented with wheat bran suppressed these adverse side effects, which was associated with the restoration of insulin-like growth factor 1 and a decrease in corticosterone levels. We have also shown that the advantageous results of the modified HFKD are not species- or sex-specific. Our data indicate that the proposed HFKD modification even allows for its application in young animals, without causing detrimental side effects.

Genetic Targeting in Cerebellar Purkinje Cells: an Update.

Since the last review paper published in Cerebellum in 2002 [1], there has been a substantial increase in the number of experiments utilizing transgenic manipulations in murine cerebellar Purkinje cells. Most of these approaches were made possible with the use of the Cre/loxP methodology and pcp2/L7 based Cre recombinase expressing transgenic mouse strains. This review aims to summarize all studies which used Purkinje cell specific transgenesis since the first use of mouse strain with Purkinje cell specific Cre expression in 2002.

Bacterial Infections and Osteoclastogenesis Regulators in Men and Women with Cholesteatoma.

One of the most distinct features of middle ear cholesteatoma is bone destruction. Aetiology of cholesteatoma is thought to be multifactorial. Endotoxins produced by bacteria are thought to initiate the inflammation process in the middle ear leading to cholesteatoma. There are physiological differences in bone metabolism between men and women. The aim of our study was the immunohistochemical evaluation of the contents of two key components of the OPG/RANK/RANKL triad-RANKL and OPG in cholesteatoma, to analyse if there are any differences between the sexes and to evaluate the bacteria species isolated from cholesteatoma just before surgical treatment and to evaluate their plausible influence on the expression of OPG and RANKL in cholesteatoma. Twenty-one adult patients with acquired cholesteatoma who underwent surgery were analysed. There were no statistically significant differences in the expression of both regulators of osteoclastogenesis between the sexes. In 38.1 % patients cholesteatoma was not infected, whereas in 61.9 % patients various bacterial infections or mycosis were found. The most frequently isolated species was Pseudomonas aeruginosa (14.29 % infections) followed by Staphylococcus aureus (9.52 % infections). There were no statistically significant differences in expression of both OPG and RANKL between uninfected and infected cholesteatomas.

Autonomic and inflammatory consequences of posttraumatic stress disorder and the link to cardiovascular disease.

Stress- and anxiety-related disorders are on the rise in both military and general populations. Over the next decade, it is predicted that treatment of these conditions, in particular, posttraumatic stress disorder (PTSD), along with its associated long-term comorbidities, will challenge the health care system. Multiple organ systems are adversely affected by PTSD, and PTSD is linked to cancer, arthritis, digestive disease, and cardiovascular disease. Evidence for a strong link between PTSD and cardiovascular disease is compelling, and this review describes current clinical data linking PTSD to cardiovascular disease, via inflammation, autonomic dysfunction, and the renin-angiotensin system. Recent clinical and preclinical evidence regarding the role of the renin-angiotensin system in the extinction of fear memory and relevance in PTSD-related immune and autonomic dysfunction is also addressed.

Ultrasonic vocalizations (USV) in the three standard laboratory mouse strains: developmental analysis.

Mice, similarly to some other rodent species, communicate with specialized sounds in the ultrasonic range called ultrasonic vocalizations (USV). Evaluation of this behavioral activity enables estimation of the social interactions in animal models of autistic spectrum disorders (ASD). Because transgenic mouse models are generated, in most cases, on the mixed 129SV/C57BL6 genetic background, we were interested if parameters that characterize USV differ between these two mouse strains. In addition, we wanted to compare these strains with the BALB/c line. In order to analyze USV, we applied the standard isolation test to newborn animals and compared standard parameters. Obtained results indicate clear differences between the 129SV and C57BL6 strains in respect to all analyzed USV parameters. Both strains behave also differently when compared with the BALB/c strain. For this reason in experiments utilizing transgenic animals, contribution of various genetic backgrounds has to be carefully considered.