The goal of this study was to determine the baroreflex influence on systolic arterial pressure (SAP) and pulse interval (PI) variability in conscious mice. SAP and PI were measured in C57Bl/6J mice subjected to sinoaortic deafferentation (SAD, n = 21) or sham surgery (n = 20). Average SAP and PI did not differ in SAD or control mice. In contrast, SAP variance was enhanced (21 +/- 4 vs. 9.5 +/- 1 mmHg2) and PI variance reduced (8.8 +/- 2 vs. 26 +/- 6 ms2) in SAD vs. control mice. High-frequency (HF: 1-5 Hz) SAP variability quantified by spectral analysis was greater in SAD (8.5 +/- 2.0 mmHg2) compared with control (2.5 +/- 0.2 mmHg2) mice, whereas low-frequency (LF: 0.1-1 Hz) SAP variability did not differ between the groups. Conversely, LF PI variability was markedly reduced in SAD mice (0.5 +/- 0.1 vs. 10.8 +/- 3.4 ms2). LF oscillations in SAP and PI were coherent in control mice (coherence = 0.68 +/- 0.05), with changes in SAP leading changes in PI (phase = -1.41 +/- 0.06 radians), but were not coherent in SAD mice (coherence = 0.08 +/- 0.03). Blockade of parasympathetic drive with atropine decreased average PI, PI variance, and LF and HF PI variability in control (n = 10) but had no effect in SAD (n = 6) mice. In control mice, blockade of sympathetic cardiac receptors with propranolol increased average PI and decreased PI variance and LF PI variability (n = 6). In SAD mice, propranolol increased average PI (n = 6). In conclusion, baroreflex modulation of PI contributes to LF, but not HF PI variability, and is mediated by both sympathetic and parasympathetic drives in conscious mice.

Resumo: O ingresso na universidade demanda novas habilidades sociais, e o seu défi cit pode trazer aos universitários difi culdades acadêmicas e interpessoais. Poucos estudos têm abordado a infl uência dos períodos da graduação e das diferenças de gêneros quanto às habilidades sociais apresentadas por universitários, inclusive quanto à frequência, à qualidade com que ocorrem, e às variáveis antecedentes e consequentes das interações. O objetivo geral deste artigo consiste em descrever as habilidades sociais apresentadas por estudantes universitários ao longo dos anos de graduação, verifi cando mudanças com o passar dos períodos letivos. Especifi camente, o estudo propõe-se à comparação de grupos de estudantes de diferentes anos (1º e 2º, 1º e 3º, 2º e 3º) dos perío-dos integral e noturno e de homens e mulheres e à apresentação das análises funcionais das interações, considerando os comportamentos e contextos mais frequentes. Foram avaliados 85 estudantes universitários do curso de Desenho Industrial, utilizando-se o Questionário de Habilidades Sociais para Universitá-rios -Comportamentos e Contexto e o Inventário de habilidades Sociais (IHS). Os resultados apontaram diferenças entre homens e mulheres e entre os perío-dos integral e noturno: as maiores diferenças residem nas comparações entre os anos, indicando que os primeiros e segundos anos necessitam de maiores investimentos em intervenções, pois apresentam maiores difi culdades em comportamentos de comunicação, expressividade e resolução de confl itos. Implicações, limitações e sugestões de estudos também são discutidas.Palavras-chave: universitários, habilidades sociais, avaliação. Abstract:The entering at the University requires new social skills and their deficits may bring to students academic and interpersonal diffi culties. Few studies have addressed the infl uence of undergraduate periods and gender diff er- IntroduçãoNa sociedade moderna, as relações interpessoais são muito importantes, pois independentemente de suas atividades profissionais exige-se dos indivíduos desempenhos sociais aceitáveis e elaborados, o que faz com que a temática das habilidades sociais e seus correlatos sejam particularmente interessantes (Barreto et al., 2004).Nesse contexto, os estudantes universitá-rios constituem uma classe profissional emergente que apresenta, pelo menos em algumas áreas, a interação social como base de sua atuação profissional, quer como objeto ou objetivo dessa atuação. Na vida universitária, um repertório de habilidades interpessoais e de desempenho de falar em público pode ser considerado imprescindível para um melhor desempenho acadêmico e social dos indivíduos. Para esse grupo, a necessidade de avaliação do desempenho social assume inquestionável relevância social e educacional, pois o comprometimento social e funcional se evidencia em prejuízos para a qualidade de vida desses indivíduos (Angélico, 2009).As Habilidades Sociais (HS), dentro do contexto acadêmico, não estão somente relacionadas ao desempenho profissional e ao ajuste do indivíduo na...

The effect of pyridostigmine (PYR) - an acetylcholinesterase inhibitor - on hemodynamics and cardiac autonomic control, was never studied in conscious myocardial infarcted mice. Telemetry transmitters were implanted into the carotid artery under isoflurane anesthesia. Seven to ten days after recovery from the surgery, basal arterial pressure and heart rate were recorded, while parasympathetic and sympathetic tone (ΔHR) was evaluated by means of methyl atropine and propranolol. After the basal hemodynamic recording the mice were subjected to left coronary artery ligation for producing myocardial infarction (MI), or sham operation, and implantation of minipumps filled with PYR or saline. Separate groups of anesthetized (isoflurane) mice previously (4 weeks) subjected to MI, or sham coronary artery ligation, were submitted to cardiac function examination. The mice exhibited an infarct length of approximately 12%, no change in arterial pressure and increased heart rate only in the 1st week after MI. Vagal tone decreased in the 1st week, while the sympathetic tone was increased in the 1st and 4th week after MI. PYR prevented the increase in heart rate but did not affect the arterial pressure. Moreover, PYR prevented the increase in sympathetic tone throughout the 4 weeks. Concerning the parasympathetic tone, PYR not only impaired its attenuation in the 1st week, but enhanced it in the 4th week. MI decreased ejection fraction and increased diastolic and systolic volume. Therefore, the pharmacological increase of peripheral acetylcholine availability by means of PYR prevented tachycardia, increased parasympathetic and decreased sympathetic tone after MI in mice.

This study evaluated the role of arterial baroreceptors in arterial pressure (AP) and pulse interval (PI) regulation in conscious C57BL mice. Male animals, implanted with catheters in a femoral artery and a jugular vein, were submitted to sino-aortic (SAD), aortic (Ao-X) or carotid sinus denervation (Ca-X), 5 days prior to the experiments. After basal recording of AP, the lack of reflex bradycardia elicited by administration of phenylephrine was used to confirm the efficacy of SAD, and cardiac autonomic blockade with methylatropine and propranolol was performed. The AP and PI variability were calculated in the time and frequency domains (spectral analysis/fast Fourier transform) with the spectra quantified in low-(LF; 0.25-1 Hz) and high-frequency bands (HF; 1-5 Hz). Basal AP and AP variability were higher after SAD, Ao-X or Ca-X than in intact mice. Pulse interval was similar among the groups, whereas PI variability was lower after SAD. Atropine elicited a slight tachycardia in control mice but did not change PI after total or partial denervation. The bradycardia caused by propranolol was higher after SAD, Ao-X or Ca-X compared with intact mice. The increase in the variability of AP was accompanied by a marked increase in the LF and HF power of the AP spectra after baroreceptor denervation. The LF and HF power of the PI were reduced by SAD and by Ao-X or Ca-X. Therefore, both sino-aortic and partial baroreceptor denervation in mice elicits hypertension and a remarkable increase in AP variability and cardiac sympathetic tonus. Spectral analysis showed an important contribution of the baroreflex in the power of LF oscillations of the PI spectra. Both sets of baroreceptors seem to be equally important in the autonomic regulation of the cardiovascular system in mice.

BackgroundIn spite of a large amount of studies in anesthetized animals, isolated hearts, and in vitro cardiomyocytes, to our knowledge, myocardial function was never studied in conscious diabetic rats. Myocardial performance and the response to stress caused by dobutamine were examined in conscious rats, fifteen days after the onset of diabetes caused by streptozotocin (STZ). The protective effect of insulin was also investigated in STZ-diabetic rats.MethodsCardiac contractility and relaxation were evaluated by means of maximum positive (+dP/dtmax) and negative (-dP/dtmax) values of first derivative of left ventricular pressure over time. In addition, it was examined the myocardial response to stress caused by two dosages (1 and 15 μg/kg) of dobutamine. One-way analysis of variance (ANOVA) was used to compare differences among groups, and two-way ANOVA for repeated measure, followed by Tukey post hoc test, to compare the responses to dobutamine. Differences were considered significant if P < 0.05.ResultsBasal mean arterial pressure, heart rate, +dP/dtmax and -dP/dtmax were found decreased in STZ-diabetic rats, but unaltered in control rats treated with vehicle and STZ-diabetic rats treated with insulin. Therefore, insulin prevented the hemodynamic and myocardial function alterations observed in STZ-diabetic rats. Lower dosage of dobutamine increased heart rate, +dP/dtmax and -dP/dtmax only in STZ-diabetic rats, while the higher dosage promoted greater, but similar, responses in the three groups. In conclusion, the results indicate that myocardial function was remarkably attenuated in conscious STZ-diabetic rats. In addition, the lower dosage of dobutamine uncovered a greater responsiveness of the myocardium of STZ-diabetic rats. Insulin preserved myocardial function and the integrity of the response to dobutamine of STZ-diabetic rats.ConclusionThe present study provides new data from conscious rats showing that the cardiomyopathy of this pathophysiological condition was expressed by low indices of contractility and relaxation. In addition, it was also demonstrated that these pathophysiological features were prevented by the treatment with insulin.