37 resultados para Vagal Tone
Resumo:
The voltage-gated potassium channel subunit Kv3.1 confers fast firing characteristics to neurones. Kv3.1b subunit immunoreactivity (Kv3.1b-IR) was widespread throughout the medulla oblongata, with labelled neurones in the gracile, cuneate and spinal trigeminal nuclei. In the nucleus of the solitary tract (NTS), Kv3.1b-IR neurones were predominantly located close to the tractus solitarius (TS) and could be GABAergic or glutamatergic. Ultrastructurally, Kv3.1b-IR was detected in NTS terminals, some of which were vagal afferents. Whole-cell current-clamp recordings from neurones near the TS revealed electrophysiological characteristics consistent with the presence of Kv3.1b subunits: short duration action potentials (4.2 +/- 1.4 ms) and high firing frequencies (68.9 +/- 5.3 Hz), both sensitive to application of TEA (0.5 mm) and 4-aminopyridine (4-AP; 30 mum). Intracellular dialysis of an anti-Kv3.1b antibody mimicked and occluded the effects of TEA and 4-AP in NTS and dorsal column nuclei neurones, but not in dorsal vagal nucleus or cerebellar Purkinje cells (which express other Kv3 subunits, but not Kv3.1b). Voltage-clamp recordings from outside-out patches from NTS neurones revealed an outward K(+) current with the basic characteristics of that carried by Kv3 channels. In NTS neurones, electrical stimulation of the TS evoked EPSPs and IPSPs, and TEA and 4-AP increased the average amplitude and decreased the paired pulse ratio, consistent with a presynaptic site of action. Synaptic inputs evoked by stimulation of a region lacking Kv3.1b-IR neurones were not affected, correlating the presence of Kv3.1b in the TS with the pharmacological effects.
Resumo:
Endothelial dysfunction and an associated increase in vascular tone are risk factors for cardiovascular disease and highly predictive of future cardiovascular events. A part of the benefits associated with increased intake of the long chain (LC) n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid and docosahexaenoic acid, found in fish oils is a positive impact on cardiovascular health. Here, the recent evidence from human observational and intervention trials are reviewed, and an insight into potential mechanisms underlying the impact of LC n-3 PUFA on vascular reactivity is provided.
Resumo:
The actor’s body is of critical importance to the biopic’s representation of ‘real’ lives, to issues of physical and gestural resemblance, and in its role as the dramatic vehicle; acting out significant moments, embodying transformations. Through detailed examination of Beyond the Sea (2004), De-Lovely (2004), Molière (2007), films which foreground the construction, and constructedness, of life through performance and spectacle, this chapter explores the self-reflexive and intertexual embodiment of life stories. It focuses on the material details of performance in relation to distinctly contemporary strategies of film style and tone, and how these connect to questions of expectation and agency.
Resumo:
Animal studies find that prenatal stress is associated with increased physiological and emotional reactivity later in life, mediated via fetal programming of the HPA axis through decreased glucocorticoid receptor (GR) gene expression. Post-natal behaviours, notably licking and grooming in rats, cause decreased behavioural indices of fear and reduced HPA axis reactivity mediated via increased GR gene expression. Post-natal maternal behaviours may therefore be expected to modify prenatal effects, but this has not previously been examined in humans. We examined whether, according to self-report, maternal stroking over the first weeks of life modified associations between prenatal depression and physiological and behavioral outcomes in infancy, hence mimicking effects of rodent licking and grooming. From a general population sample of 1233 first time mothers recruited at 20 weeks gestation we drew a stratified random sample of 316 for assessment at 32 weeks based on reported inter-partner psychological abuse, a risk to child development. Of these 271 provided data at 5, 9 and 29 weeks post delivery. Mothers reported how often they stroked their babies at 5 and 9 weeks. At 29 weeks vagal withdrawal to a stressor, a measure of physiological adaptability, and maternal reported negative emotionality were assessed. There was a significant interaction between prenatal depression and maternal stroking in the prediction of vagal reactivity to a stressor (p = .01), and maternal reports of infant anger proneness (p = .007) and fear (p = .043). Increasing maternal depression was associated with decreasing physiological adaptability, and with increasing negative emotionality, only in the presence of low maternal stroking. These initial findings in humans indicate that maternal stroking in infancy, as reported by mothers, has effects strongly resembling the effects of observed maternal behaviours in animals, pointing to future studies of the epigenetic, physiological and behavioral effects of maternal stroking.
Resumo:
Associations between low birth weight and prenatal anxiety and later psychopathology may arise from programming effects likely to be adaptive under some, but not other, environmental exposures and modified by sex differences. If physiological reactivity, which also confers vulnerability or resilience in an environment-dependent manner, is associated with birth weight and prenatal anxiety, it will be a candidate to mediate the links with psychopathology. From a general population sample of 1,233 first-time mothers recruited at 20 weeks gestation, a sample of 316 stratified by adversity was assessed at 32 weeks and when their infants were aged 29 weeks (N = 271). Prenatal anxiety was assessed by self-report, birth weight from medical records, and vagal reactivity from respiratory sinus arrhythmia during four nonstressful and one stressful (still-face) procedure. Lower birth weight for gestational age predicted higher vagal reactivity only in girls (interaction term, p = .016), and prenatal maternal anxiety predicted lower vagal reactivity only in boys (interaction term, p = .014). These findings are consistent with sex differences in fetal programming, whereby prenatal risks are associated with increased stress reactivity in females but decreased reactivity in males, with distinctive advantages and penalties for each sex.
Resumo:
Two varieties of Greek are spoken on the island of Cyprus: the local dialect, namely the Greek-Cypriot Dialect (GCD), and Standard Modern Greek (SMG). English is also influential, as Cyprus was an English colony until 1960. The dialect is rarely employed for everyday written purposes; however, it is now evident in computer-mediated communication (CMC). As a contribution to the field of code-switching in writing, this study examines how Greek-Cypriot internet users employ GCD, SMG, and English in their Facebook interactions. In particular, we investigate how identities (discursive and social) are performed and indexed through the linguistic choices of Greek-Cypriot internet users. The findings indicate that switches to GCD add a humorous tone and express solidarity and informality. SMG is mostly used for ‘official’ statements, and it is preferred by mature internet users, while English is used with expressions of affect and evaluative comments.
Resumo:
'O Testamento de Dom Quixote', 'script' by Glauber Rocha, is supposed to be loosely inspired in the last chapter of Cervantes' novel, although it is absolutely different from it: in the film the character doesn't recover his lucidity, but he lives surrounded by mystical delirium. Already in its first pages, it is obvious that it is a first draft of 'Cutting Heads', the film he shot in Spain in 1970, in spite of being completely different from the final movie. The comparison between both works allows us to see to what extent this essential seed was a forgotten one: the film was always publicised as a version of 'Macbeth', a reference which is missing here, and the 'Quijote' was never considered a point of depart, although its work with reality and dream determined the tone of the film from the very beginning.