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1.
Transl Psychiatry ; 6(12): e977, 2016 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-27959334

RESUMO

Sexual abuse contributes to the development of multiple forms of psychopathology, including anxiety and depression, but the extent to which genetics contributes to these disorders among sexual abuse victims remains unclear. In this translational study, we first examined gene expression in the brains of rodents exposed to different early-life conditions (long, brief or no maternal separation). Hypothesizing that genes revealing changes in expression may have relevance for psychiatric symptoms later in life, we examined possible association of those genes with symptoms of anxiety and depression in a human sample of sexual abuse victims. Changes in rodent brain gene expression were evaluated by means of correspondence and significance analyses of microarrays by comparing brains of rodents exposed to different early-life conditions. Tag single-nucleotide polymorphisms (SNPs) of resulting candidate genes were genotyped and tested for their association with symptoms of anxiety and depression (Hospital Anxiety and Depression Scale) in a sample of 361 sexual abuse victims, using multinomial logistic regression. False discovery rate was applied to account for multiple testing in the genetic association study, with q-value of 0.05 accepted as significant. We identified four genes showing differential expression among animals subjected to different early-life conditions as well as having potential relevance to neural development or disorders: Notch1, Gabrr1, Plk5 and Zfp644. In the human sample, significant associations were observed for two NOTCH1 tag SNPs: rs11145770 (OR=2.21, q=0.043) and rs3013302 (OR=2.15, q=0.043). Our overall findings provide preliminary evidence that NOTCH1 may be implicated in the susceptibility to anxiety and depression among sexual abuse victims. The study also underscores the potential importance of animal models for future studies on the health consequences of early-life stress and the mechanisms underlying increased risk for psychiatric disorders.


Assuntos
Transtornos de Ansiedade/genética , Transtorno Depressivo/genética , Expressão Gênica/genética , Predisposição Genética para Doença/genética , Receptor Notch1/genética , Delitos Sexuais/psicologia , Alelos , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Acontecimentos que Mudam a Vida , Masculino , Transtornos do Neurodesenvolvimento/genética , Polimorfismo de Nucleotídeo Único/genética , Ratos Wistar , Pesquisa Translacional Biomédica
2.
Stress ; 15(6): 658-70, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22356167

RESUMO

We compared the consequences of two stressors, 'unnatural' inescapable footshocks (IFSs) and 'natural' social defeat (SD), on behaviours typically sensitive to stress [sucrose preference, open field (OF), elevated plus maze (EPM) and acoustic startle responses (ASRs)] and the association with pre-stressor plasma corticosterone concentration. After initial blood sampling, rats (n = 20 per group) were exposed to either 10 IFSs (1 mA intensity, 5 s duration each) or to 1 h SD (defeat by an aggressive resident male rat and further exposure but separated in a small cage) or to control procedures (handling). Rats were tested once for ASR (day 19), while the other behavioural tests were applied once weekly for 3 weeks. Both stress groups showed short-lasting lowered sucrose preference, and in the EPM they showed shorter total distance moved, shorter distance moved on open arms and less time on open arms compared to controls. In the OF test, IFS rats showed shorter total distance moved up to 2 weeks after stress. The SD group showed shorter total distance moved in the OF, which was only significant 2 weeks after stress. Low pre-stressor plasma corticosterone concentration was only associated with defecation (IFS rats) and latency to enter open arms in the EPM (all low corticosterone subgroups, n = 10 per subgroup). SD rats with high initial plasma corticosterone concentration showed enhanced ASR compared to the other subgroups with high initial plasma corticosterone concentration (n = 9 per subgroup). The results indicate that footshock and SD, while generally leading to an increase in anxiety behaviours, represent qualitatively different stressors.


Assuntos
Ansiedade/sangue , Corticosterona/sangue , Estimulação Elétrica , Predomínio Social , Estresse Psicológico , Animais , Comportamento Animal/fisiologia , , Masculino , Aprendizagem em Labirinto , Ratos , Ratos Wistar , Reflexo de Sobressalto , Estresse Fisiológico , Estresse Psicológico/fisiopatologia , Tempo
3.
Physiol Behav ; 105(4): 1058-66, 2012 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-22155491

RESUMO

Prolonged maternal separation in rats has several effects on health and behavior. Here we investigated how maternal separation might interact with social stress in adulthood on behavior and gastrointenstinal permeability. The effects of either daily 180 min long term pup-dam separation (LMS) during the stress hyporesponsive period or daily 10 min brief maternal separation (BMS) on behavior, corticosterone and intestinal permeability were investigated, compared to a non-handling (NH) condition in male offspring. The animals from each separation condition were then randomly assigned to adult stress and control conditions, where the stress condition was exposure to 14 days of social instability (CSI). Sucrose preference, elevated plus maze behavior and corticosterone were measured. Colitis was experimentally induced by dextran sulfate sodium for 7 days, followed by measurement of intestinal permeability using the (51)CrEDTA method. Granulocyte marker protein was measured in feces and colons were examined histologically for inflammation. Prior to the social stress, the LMS offspring showed elevated corticosterone levels, lower elevated plus maze activity and less fluid consumption. After social stress, corticosterone levels were suppressed in LMS animals and again they showed less fluid consumption. LMS animals had significantly higher intestinal permeability, but only when also exposed to the social stress in adulthood. The current results support a two-hit model, whereby early life events interact with adult life events in altering animals' vulnerability.


Assuntos
Absorção Intestinal/fisiologia , Privação Materna , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia , Animais , Peso Corporal/fisiologia , Colite/induzido quimicamente , Colite/fisiopatologia , Corticosterona/sangue , Fezes/química , Complexo Antígeno L1 Leucocitário/análise , Masculino , Aprendizagem em Labirinto/fisiologia , Ratos , Ratos Wistar , Estresse Psicológico/sangue , Fatores de Tempo
4.
Neurosci Biobehav Rev ; 35(5): 1291-301, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21316391

RESUMO

With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely aversive conditions, is in our view inappropriate. Review of the literature reveals that the physiological 'stress' response to appetitive, rewarding stimuli that are often not considered to be stressors can be as large as the response to negative stimuli. Analysis of the physiological response during exercise supports the view that the magnitude of the neuroendocrine response reflects the metabolic and physiological demands required for behavioural activity. We propose that the term 'stress' should be restricted to conditions where an environmental demand exceeds the natural regulatory capacity of an organism, in particular situations that include unpredictability and uncontrollability. Physiologically, stress seems to be characterized by either the absence of an anticipatory response (unpredictable) or a reduced recovery (uncontrollable) of the neuroendocrine reaction. The consequences of this restricted definition for stress research and the interpretation of results in terms of the adaptive and/or maladaptive nature of the response are discussed.


Assuntos
Recompensa , Estresse Fisiológico/fisiologia , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia , Adaptação Fisiológica/fisiologia , Animais , Corticosterona/sangue , Humanos , Sistema Hipotálamo-Hipofisário/metabolismo , Sistema Hipotálamo-Hipofisário/fisiopatologia , Sistema Hipófise-Suprarrenal/metabolismo , Sistema Hipófise-Suprarrenal/fisiopatologia , Valor Preditivo dos Testes , Estresse Psicológico/sangue
5.
Tech Coloproctol ; 14(2): 175-9, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20390316

RESUMO

BACKGROUND: The purpose of the study was the measurement of the anal cushion area using static transperineal ultrasound in a group of patients with symptomatic grade III and IV haemorrhoids about to undergo haemorrhoidectomy and compare them with a group of age-matched normals and the measured area following haemorrhoidectomy. METHODS: Transperineal sonography was performed using a linear transducer measuring the anal cushion area by subtracting the measured luminal diameter of the undisturbed anal canal from the inner border of the internal anal sphincter. Measures were made 6 weeks following haemorrhoidectomy. RESULTS: Comparisons were made between 22 normals and 36 patients with haemorrhoids (31 evaluable post-operatively). The median area of normals was 0.78 cm², that of pre-operative patients 2.25 cm² and that of post-operative cases 1.20 cm². There was a significant difference between pre- and post-operative cases with cushion areas of normal patients being significantly lower than post-operative cases. Variance of measurement in all 3 groups was negligible. CONCLUSION: Static transperineal sonography measuring the anal cushion area is reproducible and shows marked differences between normals and patients with symptomatic haemorrhoids. There is a marked effect on measured area resultant from haemorrhoidectomy.


Assuntos
Canal Anal/diagnóstico por imagem , Canal Anal/patologia , Hemorroidas/diagnóstico por imagem , Hemorroidas/patologia , Adulto , Idoso , Hemorroidas/cirurgia , Humanos , Mucosa Intestinal/diagnóstico por imagem , Mucosa Intestinal/patologia , Pessoa de Meia-Idade , Períneo , Projetos Piloto , Ultrassonografia
6.
Phys Med Biol ; 53(23): 6641-52, 2008 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-18997272

RESUMO

Second harmonic generation microscopy was performed on both normal and diseased breast tissue. Differences in the collagen fibre shape between normal, benign and malignant breast tissue were compared and quantified using elliptical Fourier analysis. Principal shape analysis of these coefficients provided an understanding of the key differences in collagen fibre shape between the three tissue types. A Gaussian model was also used to associate the shape of the fibre with the probability that it had been sampled from malignant breast tissue. These results provide quantitative evidence for the alteration of collagen fibre shape in both benign and malignant breast tissue.


Assuntos
Neoplasias da Mama/ultraestrutura , Colágeno/ultraestrutura , Adulto , Idoso , Idoso de 80 Anos ou mais , Mama/patologia , Mama/ultraestrutura , Neoplasias da Mama/patologia , Feminino , Análise de Fourier , Humanos , Microscopia Eletrônica , Pessoa de Meia-Idade , Software
7.
Phys Med Biol ; 52(21): 6543-53, 2007 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-17951861

RESUMO

Small angle x-ray scattering (SAXS) patterns of benign and malignant brain tumour tissue were examined. Independent component analysis was used to find a feature set representing the images collected. A set of coefficients was then used to describe each image, which allowed the use of the statistical technique of flexible discriminant analysis to discover a hidden order in the data set. The key difference was found to be in the intensity and spectral content of the second and fourth order myelin scattering peaks. This has clearly demonstrated that significant differences in the structure of myelin exist in the highly malignant glioblastoma multiforme as opposed to the benign: meningioma and schwannoma.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/diagnóstico , Glioblastoma/diagnóstico por imagem , Glioblastoma/diagnóstico , Meningioma/diagnóstico por imagem , Meningioma/diagnóstico , Bainha de Mielina/química , Neurilemoma/diagnóstico por imagem , Neurilemoma/diagnóstico , Encéfalo/metabolismo , Encéfalo/patologia , Diagnóstico Diferencial , Humanos , Modelos Estatísticos , Modelos Teóricos , Bainha de Mielina/metabolismo , Radiografia , Espalhamento de Radiação , Raios X
8.
Phys Med Biol ; 51(10): 2465-77, 2006 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-16675863

RESUMO

This paper reports on the application of wavelet decomposition to small-angle x-ray scattering (SAXS) patterns from human breast tissue produced by a synchrotron source. The pixel intensities of SAXS patterns of normal, benign and malignant tissue types were transformed into wavelet coefficients. Statistical analysis found significant differences between the wavelet coefficients describing the patterns produced by different tissue types. These differences were then correlated with position in the image and have been linked to the supra-molecular structural changes that occur in breast tissue in the presence of disease. Specifically, results indicate that there are significant differences between healthy and diseased tissues in the wavelet coefficients that describe the peaks produced by the axial d-spacing of collagen. These differences suggest that a useful classification tool could be based upon the spectral information within the axial peaks.


Assuntos
Inteligência Artificial , Neoplasias da Mama/classificação , Neoplasias da Mama/diagnóstico por imagem , Reconhecimento Automatizado de Padrão/métodos , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Difração de Raios X/métodos , Algoritmos , Diagnóstico Diferencial , Feminino , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Software
9.
Biol Reprod ; 69(3): 1079-84, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12773419

RESUMO

The circulating concentrations of progesterone, FSH, and follistatin across the estrous cycle and gestation were compared in Australian merino sheep that were homozygous for the Booroola gene, FecB, or were noncarriers. The Booroola phenotype is due to a point mutation in the bone morphogenetic protein receptor 1B. Progesterone concentrations began to rise earlier and were higher in the Booroola ewes than in the noncarriers on most days of the luteal phase but not during the follicular phase of the cycle. Follistatin concentrations remained unchanged across the estrous cycle in both groups of ewes, with no differences between genotypes. FSH concentrations were higher in Booroola ewes than in noncarrier ewes on most days of the estrous cycle, with a significantly higher and broader peak of FSH around the time of estrus. Progesterone concentrations were significantly higher in early and midgestation in Booroola ewes but were lower toward the end of gestation than those in noncarriers. FSH declined in both groups across gestation, with lower concentrations of FSH in Booroola ewes during midgestation. Follistatin remained unchanged across gestation in Booroola ewes and noncarrier ewes with a twin pregnancy but declined across gestation in noncarrier ewes with a singleton pregnancy. These results suggest that follistatin concentration is not regulated by the FecB gene during the estrous cycle and pregnancy but is influenced by the number of fetuses. However, the FecB gene appears to positively affect both progesterone and FSH during the estrous cycle and across pregnancy, which suggests that bone morphogenetic proteins play an important role in the regulation of both hormones.


Assuntos
Ciclo Estral/sangue , Hormônio Foliculoestimulante/sangue , Folistatina/sangue , Gravidez/sangue , Progesterona/sangue , Proteínas Serina-Treonina Quinases/genética , Receptores de Fatores de Crescimento/genética , Ovinos/genética , Ovinos/metabolismo , Animais , Receptores de Proteínas Morfogenéticas Ósseas Tipo I , Ciclo Estral/genética , Feminino , Fertilidade/genética , Genótipo , Heterozigoto , Homozigoto , Ovulação/sangue , Ovulação/genética , Periodicidade , Mutação Puntual , Gravidez/genética
10.
Integr Physiol Behav Sci ; 36(1): 75-83, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11484998

RESUMO

The discovery of the importance of bacterial factors in the etiology of ulcer disease has led to a neglect of psychological factors. However, both earlier theoretical and empirical approaches implicating these factors are supported by more recent studies, both epidemiological and experimental. While not ignoring the unquestioned role of Helicobacter, it is important for future research to recognize the multi-factorial nature of ulcer disease by which several factors, including stress, bacteria and non-steroid antiinflammatory drugs, may interact to drive a pre-pathology (erosions or ulcerations) to a pathological state (ulcer). Calls for general eradication programs should be cautioned in the light of possible unwanted side effects.


Assuntos
Úlcera Gástrica/psicologia , Animais , Infecções por Helicobacter/microbiologia , Humanos , Úlcera Gástrica/etiologia , Úlcera Gástrica/microbiologia , Estresse Psicológico/complicações
11.
Alcohol Alcohol ; 36(1): 48-58, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11139416

RESUMO

Based upon repeated observations of a relationship between defensive burying (DB), ethanol intake and stress ulcer susceptibility, and recurring questions regarding what DB behaviour reflects, two experiments were performed. Experiment 1 showed that prod shock exposure per se reduced subsequent ethanol intake, as did access to burying material. In rats without burying material in the conditioning phase, subsequent access to ethanol resulted in reduced DB activity in the retest, pointing to some interference by ethanol on latent learning. Experiment 2 showed that there were no effects of anxiety as measured in the elevated plus-maze (EPM) on saccharin or ethanol intake. Behaviours in the EPM and DB test did not correlate. Rats entering the open arm on first entry into the EPM drank and preferred more ethanol than those choosing the closed arm. Saccharin intake was negatively related to burying latency, and positively related to initial ethanol intake. In conclusion, it is still questionable whether the DB test is measuring anxiety, but exposure to the test or performance of the DB activity appears to cause modifications, psychologically and perhaps physiologically, in rats. Ethanol intake may under certain conditions interfere with the acquisition of a defensive response. The testing of DB behaviour may be useful in studying drug effects on latent learning of prepared responses.


Assuntos
Adaptação Psicológica , Consumo de Bebidas Alcoólicas/psicologia , Ansiedade/psicologia , Comportamento Animal , Condicionamento Psicológico , Estresse Psicológico/psicologia , Animais , Masculino , Ratos , Retenção Psicológica
12.
Br Poult Sci ; 41(2): 219-23, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10890220

RESUMO

1. Two strains of layers were fed compound or choice forms of a standard diet and given calcium as either ground limestone or coarse limestone grit daily or every 2nd day. Mortality caused by Marek's disease was monitored during the rearing and laying phases. 2. A dramatic difference in Marek's disease mortality was found between the strains. Heavy Marek's disease mortality in the imported strain A in the rearing phase was not markedly affected by dietary or calcium treatment. 3. Method of feeding and calcium provision interacted to influence significantly the risk of death due to Marek's disease in the laying phase in layer strain A. 4. Choice feeding may adversely influence Marek's disease losses in layers.


Assuntos
Cálcio da Dieta/administração & dosagem , Galinhas , Doença de Marek/dietoterapia , Ração Animal , Animais , Austrália/epidemiologia , Peso Corporal , Cálcio/metabolismo , Surtos de Doenças/veterinária , Ingestão de Alimentos , Feminino , Doença de Marek/mortalidade , Modelos de Riscos Proporcionais , Distribuição Aleatória
13.
Behav Brain Res ; 110(1-2): 161-74, 2000 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-10802312

RESUMO

When an organism is subjected to stress, gastric ulcers or ulcerations commonly develop but the vulnerability to and amount of pathology induced varies considerably between individuals. The role of psychological factors in determining the occurrence and severity of these ulcerations is amply demonstrated in the studies reviewed here. The present paper (a) gives a brief history of the search for the causes of gastric ulcer, (b) provides a review of our own research which reveals that vulnerability to gastric ulceration is modulated by psychologically meaningful experiences, and (c) offers a multifactorial perspective on the causes of gastric ulceration and the future of research on it.


Assuntos
Ansiedade/psicologia , Desamparo Aprendido , Úlcera Gástrica/fisiopatologia , Estresse Psicológico/psicologia , Animais , Humanos
14.
Physiol Behav ; 68(5): 723-33, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10764903

RESUMO

The purpose of this study was to investigate the relationship between the startle response and ethanol. Aspects of the startle response, including initial and average startle, habituation, and prepulse inhibition (PPI) were studied. The startle response was measured to detect potential predictors of voluntary ethanol consumption and to observe whether ethanol ingestion would affect startle in subsequent tests. Rats were tested three times in a standard startle chamber. After the initial startle test, rats categorized as showing high or low PPI were allocated in a balanced way to a free-choice ethanol-water regime or to the water-regime control group. At the end of the ethanol period (lasting for 16 days, including access to ethanol for 10 days), the rats were tested again in the startle chamber 24 h after ethanol removal. After 5 weeks of ethanol abstinence, rats were exposed to a final startle test. The response to the first 120-dB stimulus showed an inverted U-shaped, curvilinear relationship to later ethanol consumption. Startle habituation appeared to have predictive value regarding ethanol consumption, with rats showing the most efficient habituation drinking most. Data showed no relationship between PPI and ethanol intake. Rats given access to ethanol showed greater habituation in the post-ethanol test than did the water controls. After 5 weeks of abstinence, low ethanol-consuming rats showed lower startle responses to the first 120-dB stimulus than did high ethanol-consuming rats. The present data suggest a two-way relationship between startle response characteristics and alcohol.


Assuntos
Etanol/farmacologia , Plasticidade Neuronal/efeitos dos fármacos , Reflexo de Sobressalto/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Habituação Psicofisiológica/efeitos dos fármacos , Inibição Psicológica , Masculino , Plasticidade Neuronal/fisiologia , Ratos , Ratos Wistar , Reflexo de Sobressalto/fisiologia , Tempo
15.
Psychiatry Res ; 85(1): 39-50, 1999 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-10195315

RESUMO

Within the Cognitive Activation Theory of Stress (CATS), the stress response occurs whenever there is a discrepancy between what the organism is expecting, and what really exists. It affects the biochemistry of the brain, mobilizes resources, affects performance, and endocrine, vegetative, and immune systems. Initial positive feedback and feed-forward mechanisms are gradually changed by homeostatic mechanisms. Slower reactive hormones such as cortisol seem to dampen the initial response. The time course may depend on psychological mechanisms. Subjects with efficient coping show the fast- and short-lasting catecholamine response, while subjects with high defense mechanisms (related to stimulus expectancies) may show more signs of prolonged activation. Non-coping individuals show a sustained general activation which may develop into somatic disease or illness.


Assuntos
Nível de Saúde , Estresse Psicológico/psicologia , Sobrevida/fisiologia , Adaptação Psicológica/fisiologia , Encéfalo/metabolismo , Catecolaminas/metabolismo , Mecanismos de Defesa , Eletroencefalografia , Humanos , Hidrocortisona/sangue , Hidrocortisona/metabolismo , Psiconeuroimunologia , Estresse Psicológico/metabolismo , Fatores de Tempo
16.
Stress ; 2(3): 227-30, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9787270

RESUMO

A handling-only control and two footshocked stressed groups for which the numbers of footshocks, 10 or 100, were determined by different proposed clinically relevant models were compared after a 15-day delay on the alerting-immobility response to a sudden reduction in noise. Only the 10-shocks group showed a significantly increased level of alert-immobility. The implications of this non-monotonicity of effects of increasing stress for modelling and scientific practice are considered.


Assuntos
Estresse Psicológico/fisiopatologia , Animais , Eletrochoque , Manobra Psicológica , Desamparo Aprendido , Masculino , Ratos , Ratos Sprague-Dawley , Restrição Física , Especificidade da Espécie , Estresse Psicológico/psicologia
17.
Aust Vet J ; 76(1): 54-6, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9578769

RESUMO

OBJECTIVE: To determine the rate of decline of chlorfluazuron (CFZ) concentration in the fat of cattle. DESIGN: A field depletion study. ANIMALS: Fifteen steers that had become contaminated with CFZ through eating cotton trash or cotton leaf pellets derived from CFZ-treated cotton crops. PROCEDURE: Fat samples were collected from the cattle at about 3 week intervals according to a schedule where each animal was sampled on four occasions up to 340 days after removal from the contaminated feed source. RESULTS: When the effects of dilution are removed CFZ concentrations were found to decline slowly for about 200 days. Depletion was minimal between 200 and 340 days. CONCLUSION: According to this trial, CFZ-contaminated, nonlactating cattle which have finished growing will remain contaminated. Field experience has not supported this conclusion.


Assuntos
Tecido Adiposo/metabolismo , Bovinos/metabolismo , Hormônios Juvenis/farmacocinética , Compostos de Fenilureia/farmacocinética , Piridinas/farmacocinética , Ração Animal , Animais , Contaminação de Alimentos , Gossypium , Masculino
18.
Alcohol Clin Exp Res ; 22(9): 2050-4, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9884150

RESUMO

The aim of this study was to investigate differences in shock-prod induced defensive burying and vulnerability to stress gastric ulcerations in two lines of rats selectively bred for alcohol-preference (AA) and alcohol-avoidance (ANA). Alcohol-naïve animals from the AA and ANA lines were tested in the shock-prod defensive burying test and (after an interval of approximately 2 months) in a 75 min water-immersion stress ulceration-inducing procedure. The AA rats showed longer latencies (327.5 s) for burying after shock-prod compared with the ANA animals (128.0 s). Furthermore, the ANA rats developed more stomach ulcerations (12.35 mm) compared with the AA rats (1.30 mm). Animals also differed based on whether they had been tested for defensive burying or not, with the tested animals showing less ulceration development than the control group. We hypothesize that the difference between AA and ANA rats is controlled by some common biochemical mechanism. One likely candidate is the dopaminergic system, which is involved in both the motivational effects of alcohol, as well as anxiety and stomach ulceration. In addition, the alcohol-preferring strain seems to be less fearful and generally may be less sensitive to aversive stimuli, be it shock prod, the aversive properties of alcohol, or water immersion stress.


Assuntos
Alcoolismo/genética , Nível de Alerta/genética , Comportamento Estereotipado/fisiologia , Úlcera Gástrica/genética , Estresse Psicológico/complicações , Alcoolismo/patologia , Animais , Dopamina/fisiologia , Eletrochoque , Medo/fisiologia , Mucosa Gástrica/patologia , Masculino , Motivação , Ratos , Ratos Endogâmicos , Seleção Genética , Úlcera Gástrica/patologia
19.
Stress ; 1(3): 169-178, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9787242

RESUMO

To replicate and extend results of earlier studies on amino acid effects on post-stress ulcers, rats were subjected to i.p. injections of (a) saline, (b) tryptophan, (c) tyrosine + valine or(d) tryptophan + tyrosine + valine, either 30 minutes before or immediately after one hour of water restraint stress. Gastric lesions, brain norepinephrine, serotonin and 5-hydroxyindoleacetic acid (5-HIAA) were examined after one hour of poststress rest. We hypothesised that post-stress lesions could be aggravated by central noradrenergic hypoactivity and serotonergic hyperactivity during the post-stress period. Other studies have indicated that tyrosine + valine reduces central serotonergic activity, while additional tryptophan blocks this effect. We therefore expected post-stress lesions to be reduced in tyrosine + valine but not in tryptophan + tyrosine + valine treated animals. Although these expectations were met tentatively in animals injected prior to stress, thus replicating tyrosine + valine effects we had observed earlier, opposite results were found in animals treated post-stress. The brain analyses indicate that the data cannot be explained by a norepinephrine/serotonin imbalance hypothesis. The time dependency of the effects underlines the need for caution in clinical applications of these amino acid treatments.

20.
Physiol Behav ; 61(4): 555-62, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9108575

RESUMO

Fifty rats were subjected seriatim to 6 different test tasks (open-field, startle, drug-induced sterotypy, oral finickiness, defensive burying, and memory for aversive event). This yielded 12 test-specific plus 2 general biobehavioral measures (growth and defecation). These 14 measures were subjected to factor analysis to determine if these measured tapped a common construct of "emotionality." The data yielded a 4-factor structure of Finickiness, Defensiveness, Startle-Sensitivity, and Dopaminergic-Sensitivity that accounted for 62% of the variance. Then, all rats were subjected to restraint-in-water stress to induce gastric ulcerations. Multivariate techniques tested if there was a factor or factor-structure that could predict individual differences in vulnerability to the stress-induced gastric ulcerations. Only the Dopaminergic-Sensitivity factor predicted ulcerogenic vulnerability, and its predictive power resided substantially in the latency to initiate stereotypic gnawing induced by apomorphine. This single test score correlated with amount of ulcer (r = +0.52), accounting for 25% of the variance in ulcer, suggesting that 1. prescreening rats on this variable could be a tool for reducing intrastrain experimental variance in future studies of treatments that modulate ulcerogenicity, and 2. the dopaminergic system may be intimately involved in the causal path of ulcerogenicity.


Assuntos
Análise Fatorial , Úlcera Péptica/fisiopatologia , Estresse Psicológico/fisiopatologia , Animais , Masculino , Ratos , Ratos Sprague-Dawley
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