No description available.

acase@tulane.edu / Stress is a major determinant of quality of life and chronic stress plays an important contributing role in the occurrence of psychiatric and physiological pathologies. Ascending brainstem noradrenergic afferents provide a critical excitatory drive to the hypothalamic-pituitary-adrenal (HPA) axis in response to stress by activating corticotropin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus (PVN). The stimulatory role of noradrenergic synapses on CRH neurons in the regulation of the HPA axis has long been known, but the cellular mechanisms have been perplexing. We demonstrate a retrograde inter-neuronal communication stimulated by norepinephrine that utilizes a trans-astroglial signaling mechanism to activate upstream neurons and recurrent synaptic inputs. We found that NE activates postsynaptic 1-adrenoceptors in PVN CRH neurons, which triggers a calcium response in astrocytes via the dendritic release of vasopressin. Activated astrocytes stimulate upstream glutamate neurons via ATP release and P2X receptor activation, resulting in the recurrent excitation of the CRH neurons. The NE excitation of CRH neurons is strengthened by simultaneous presynaptic 2-adrenoceptor-mediated suppression of GABA release but is restrained at higher NE concentrations by activation of upstream GABAergic neurons via the same postsynaptic α1-adrenoceptor-mediated retrograde neuronal-glial signaling mechanism. Thus, the NE stimulation of CRH neurons in the PVN is mediated by a novel retrograde signaling mechanism that enlists a trans-neuronal-astroglial circuit to activate upstream glutamate and GABA neurons. This mechanism is stress-sensitive. Acute stress desensitizes this α1-receptor mediated circuit via glucocorticoid receptor-dependent signaling. The desensitization of the excitatory circuit, through which NE exerts its major stimulatory drive to CRH neurons, indicates a cellular mechanism or a target site of negative feedback. Chronic stress desensitized the CRH neurons to both α1 and α2-adrenoceptor activation. Thus, the noradrenergic regulation of CRH neurons was lost entirely following chronic stress, rendering the CRH neurons completely insensitive to this major regulatory input. Our research revealed the cellular mechanisms of the NE regulation of CRH neurons under control, acute stress and chronic stress conditions. It fills an important gap in knowledge concerning the noradrenergic excitatory drive to the CRH neurons and the stress-induced glucocorticoid feedback control of the HPA axis. / 1 / Chun Chen

Temperament in cattle, defined as an animals response to handling by humans, had been associated with production traits such as average daily gain and meat quality, and can also be considered a welfare issue. Temperament is a stress response trait, and therefore the hypothalamic-pituitary adrenal (HPA) axis likely plays a role in determining individual animals responses. The purpose of this study was to examine whether there are associations between single nucleotide polymorphisms in two genes involved in both the HPA axis and growth, Corticotropin-releasing hormone (CRH) and Leptin (LEP), and various measurements of temperament in beef cattle. In this study, 400 crossbred beef steers were evaluated over three sessions using a traditional subjective score and three objective measurements of response to handling: Strain Gauge (absolute strain force, ASF), Movement Measurement Device and Exit Time (ET) as well as habituation for all measurements (session 3 values session 1 values). Backgrounding growth and final carcass data were also collected. The steers were genotyped at three previously reported SNPs: CRH 22C>G, CRH 240C>G and LEP 73C>T by PCR-RFLP. Subsequently, the genotypes and two-way interactions between LEP and each CRH SNP were analyzed as effects on the various temperament, growth and carcass measurements. There was a significant interaction between LEP and CRH 240C>G for ASF 1, ET 3 and ET 3-1, with the LEP CC/CRH 240C>G CC genotype appearing favorable. Additionally, the LEP CC/CRH 22C>G GG genotype appears to be favorable for ASF 1. These results indicate that it may be possible for cattle producers to select for favorable temperament using these SNPs, however these results should first be validated in additional populations.

Temperament in cattle, defined as an animals response to handling by humans, had been associated with production traits such as average daily gain and meat quality, and can also be considered a welfare issue. Temperament is a stress response trait, and therefore the hypothalamic-pituitary adrenal (HPA) axis likely plays a role in determining individual animals responses. The purpose of this study was to examine whether there are associations between single nucleotide polymorphisms in two genes involved in both the HPA axis and growth, Corticotropin-releasing hormone (CRH) and Leptin (LEP), and various measurements of temperament in beef cattle. In this study, 400 crossbred beef steers were evaluated over three sessions using a traditional subjective score and three objective measurements of response to handling: Strain Gauge (absolute strain force, ASF), Movement Measurement Device and Exit Time (ET) as well as habituation for all measurements (session 3 values session 1 values). Backgrounding growth and final carcass data were also collected. The steers were genotyped at three previously reported SNPs: CRH 22C>G, CRH 240C>G and LEP 73C>T by PCR-RFLP. Subsequently, the genotypes and two-way interactions between LEP and each CRH SNP were analyzed as effects on the various temperament, growth and carcass measurements. There was a significant interaction between LEP and CRH 240C>G for ASF 1, ET 3 and ET 3-1, with the LEP CC/CRH 240C>G CC genotype appearing favorable. Additionally, the LEP CC/CRH 22C>G GG genotype appears to be favorable for ASF 1. These results indicate that it may be possible for cattle producers to select for favorable temperament using these SNPs, however these results should first be validated in additional populations.

Research Doctorate - Doctor of Philosophy (PhD) / Pre-term birth is still the leading cause of perinatal mortality and morbidity. CRH is a hormone that is involved in the timing of labour, therefore investigation of its regulation is of importance in understanding human parturition. The CRE is a central regulatory element on the CRH promoter and in investigating proteins that bind to this element a novel protein was discovered. CREAP or cAMP Regulatory Element Associated Protein, was initially discovered by its ability to bind to the CRE. Its sequence encodes a unique set of modular domains including two zinc fingers, two leucine zippers, two coiled-coils and an RS-rich domain. These domains point to functions in both DNA binding/transcription and RNA splicing, with the leucine zippers being characteristic of bZIP transcription family and the RS domain characteristic of the SR Protein family of splicing factors, to represent a new protein family. In this thesis, molecular reagents were produced for the study of CREAP together with a polyclonal antibody. This antibody was used in western blotting to detect a 58 kDa full-length CREAP protein and a shorter 25-30 kDa truncated splice variant. CREAP was localised to the nucleus and to intranuclear splicing speckles, with co-localisation and co-immunoprecipitation with the splicing factor SC35, strongly suggesting a role in splicing. To test the transcriptional activity of CREAP, specifically if it regulates CRH expression, luciferase reporter studies were conducted. However, CREAP showed negligible effect on CRH or CRE promoter activities suggesting that it is not involved in CRH regulation. CREAP did however react with a large number of transcription factors in an in vitro assay, mostly from the bZIP and zinc finger families. siRNA mediated knockout of CREAP was conducted and the effect on genome-wide expression analysed using a microarray. CREAP knockdown caused an over-representation of genes from the protein transport, metabolism, signal transduction and transcription factor processes. Overall, CREAP appears to be a multifunctional protein that is ubiquitously expressed, and is involved in both splicing and transcriptional processes.

Research Doctorate - Doctor of Philosophy (PhD) / Pre-term birth is still the leading cause of perinatal mortality and morbidity. CRH is a hormone that is involved in the timing of labour, therefore investigation of its regulation is of importance in understanding human parturition. The CRE is a central regulatory element on the CRH promoter and in investigating proteins that bind to this element a novel protein was discovered. CREAP or cAMP Regulatory Element Associated Protein, was initially discovered by its ability to bind to the CRE. Its sequence encodes a unique set of modular domains including two zinc fingers, two leucine zippers, two coiled-coils and an RS-rich domain. These domains point to functions in both DNA binding/transcription and RNA splicing, with the leucine zippers being characteristic of bZIP transcription family and the RS domain characteristic of the SR Protein family of splicing factors, to represent a new protein family. In this thesis, molecular reagents were produced for the study of CREAP together with a polyclonal antibody. This antibody was used in western blotting to detect a 58 kDa full-length CREAP protein and a shorter 25-30 kDa truncated splice variant. CREAP was localised to the nucleus and to intranuclear splicing speckles, with co-localisation and co-immunoprecipitation with the splicing factor SC35, strongly suggesting a role in splicing. To test the transcriptional activity of CREAP, specifically if it regulates CRH expression, luciferase reporter studies were conducted. However, CREAP showed negligible effect on CRH or CRE promoter activities suggesting that it is not involved in CRH regulation. CREAP did however react with a large number of transcription factors in an in vitro assay, mostly from the bZIP and zinc finger families. siRNA mediated knockout of CREAP was conducted and the effect on genome-wide expression analysed using a microarray. CREAP knockdown caused an over-representation of genes from the protein transport, metabolism, signal transduction and transcription factor processes. Overall, CREAP appears to be a multifunctional protein that is ubiquitously expressed, and is involved in both splicing and transcriptional processes.

The effect of intracerebroventricular (ICV) injection of corticotrophin releasing hormone (CRH) and related compounds on appetite, behavior, and gastric motility in lines of chickens, one selected for low body weight (LWS) and the other high body weight (HWS), was determined. Nucleotide sequence and expression patterns of the CRHr2 receptor, involved in appetite regulation, were also determined. Some individuals of the LWS line are anorexics and many die simply from not eating while some individuals in the HWS line are compulsive eaters and exhibit obesity. CRH is a 41 residue peptide that initiates an organism's stress response and is a potent inhibitor of appetite. An ICV injection of CRH dose-dependently decreased feed intake in both lines but did not effect water intake. When CRH receptor antagonists were ICV injected an increase in feed intake in the LWS line but not in the HWS line was observed, however the appetite reducing effect of CRH was attenuated in the HWS line but not in the LWS line. The LWS line has higher concentration of corticosterone than does the HWS line. In both lines at all times treatment with CRH caused an increase in locomotion and no CRH-treated chicks from either line slept post injection. Chicks from the LWS line that were treated with CRH exhibited other anxiety related behaviors sooner than the HWS line. The LWS line showed a liner increase in crop emptying time as the dose of ICV CRH increased. The HWS line responded with a quadratic dose response to CRH treatment. Polymorphisms in the CRHr2 receptor were found in both lines in the same positions, thus we concluded these differences do not significantly contribute to body weight differences. However, differences detected in expression patterns between lines for the CRHr2 receptor may contribute to their different body weights. We conclude that differences in the CRH system, its concentrations and differential receptor action, of these two lines may be partly responsible for their altered body weight phenotype. / Ph. D.

No description available.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Bakgrund: Barnmiljöhälsorapporten 2013 indikerade att 12-åringarna i Jönköpings län känt sig besvärade av ljud i skolmatsalen. Att besväras av ljud är samma sak som att utsättas för buller. Buller har förmåga att aktivera kroppens stressystem och ljud kan bl.a. leda till ökad frisättning av kortikotropinfrisättande hormon, (CRH). Ett hormon som påverkar mag- och tarmkanalen på flera olika sätt som troligen är negativt.  Ljudstörning har förmåga att påverka hälsan hos de som utsätts, buller utgör en hälsorisk. Syfte: Syftet med detta arbete är att studera sambandet mellan bullerstörning i skolmatsalen och självskattad hälsa hos 858 12-åringar i Jönköpings län som deltagit i Barnmiljöhälsoenkäten 2011. Metod: Analyser av data från Barnmiljöhälsoenkäten 2011 där upplevelse av ljudstörning i skolmatsalen satts i relation till självskattad hälsa. Resultat: 12-åringarna i Barnmiljöhälsoenkäten 2011 i Jönköpings län som störts mest av ljud i skolmatsalen har en sämre självskattad hälsa än de som störts mindre eller inte alls av ljud i skolmatsalen. Slutsats: För att skapa bättre förutsättningar för en god hälsa hos barn bör fler studier utföras där de stresshormoner ljud kan öka frisättningen av och dess hälsoeffekter utreds. Detta eftersom denna studie indikerar en sämre självskattad hos de deltagare som upplever ljudstörning i skolmatsalen. / Background: The child health report of 2013 was undertaken in the district of Jönköping, Sweden. The results of this survey indicated that the 12 year olds that participated in the study were bothered by the noise in the dining area of their school. An elevated level of noise can affect the human body in a negative way, and can lead to an increased level of stress. Exposure to elevated levels of noise gives enhanced excretion of corticotrophin releasing hormone (CRH). CRH is a hormone that can have a negative impact on the normal function of the gastrointestinal tract. Elevated noise will affect the health of people being exposed, and entails a health hazard. Aim: The aim of this study was to evaluate the relationship between the noise in school dining areas and the self reflected health of 858 12 year old students from the district of Jönköping, Sweden. Method: The analysis was based on a child health survey 2011; evaluating the student´s reflection of the exposure of noise in relation to their own estimated health status. Results: The results from the child health survey 2011 did show that the students being most affected by noise also experienced a lower self reflected health compared to the students less affected by noise in the school dining area.  Conclusion: The findings of this study indicate that students experience an overall lower level of health if they feel negatively affected by noise. To be able to improve child health, further research needs to be undertaken regarding this issue. The effects of stress hormones need to be investigated further, as well as the relationship between excretions of stress hormones in the body and the level of surrounding noise.