Biological research
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Biological research · Jan 1999
ReviewVasopressin and bradykinin receptors in the kidney: implications for tubular function.
Vasopressin and bradykinin are two of the most important peptides in regulating vascular tone, water, and ionic balance in the body, and thus they play a key role in controlling blood pressure. In addition to being a potent vasoconstrictor, Vasopressin also has an antidiuretic activity in the kidney, whereas kinins regulate renal blood flow in addition to their vasodilatory and natriuretic activity. We review here the primary evidence for the localization of the vasopressin and kinin receptors and their role in ionic and water regulation in the kidney.
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Biological research · Jan 1995
ReviewThe activation of bulbo-spinal controls by peripheral nociceptive inputs: diffuse noxious inhibitory controls.
Some neurones in the dorsal horn of the spinal cord are strongly inhibited when a nociceptive stimulus is applied to any part of the body, distinct from their excitatory receptive fields. This phenomenon was termed "Diffuse Noxious Inhibitory Controls" (DNIC). DNIC influence only convergent neurones, and these inhibitions can be triggered only by conditioning stimuli which are nociceptive. ⋯ In other words, the descending inhibitory controls may play a physiological role in the detection of nociceptive signals. It is proposed that DNIC constitute both a filter which allows the extraction of the signal for pain and an amplifier in the transmission system which increases the potential alarm function of the nociceptive signals. This hypothesis is supported by the finding that DNIC are blocked by low doses of morphine in both rat and man.
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Biological research · Jan 2014
Association of serum total bilirubin levels with diastolic dysfunction in heart failure with preserved ejection fraction.
Left ventricular diastolic dysfunction is one of the main characteristics of heart failure patients with a preserved left ventricular ejection fraction. As bilirubin is regarded as an important endogenous antioxidant molecule, serum total bilirubin levels were compared between heart failure patients with a preserved left ventricular ejection fraction and normal controls in this study. We recruited 327 heart failure patients with a preserved left ventricular ejection fraction and 200 healthy controls. Patients were divided into 4 subgroups by their comprehensive echocardiographic manifestations, 1-mild, 2-moderate, 3-severe (reversible restrictive), 4-severe (fixed restrictive). Total bilirubin levels were compared using stepwise multiple regressions adjusted for selected factors. ⋯ TB level was negatively correlated with left ventricular diastolic dysfunction in heart failure patients with a preserved left ventricular ejection fraction, which might provide a new insight into the complicated mechanisms of heart failure with a preserved left ventricular ejection fraction.
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In memoriam Professor Hugo Adrian, born 1926, deceased 1994, in Santiago, Chile. After completion of his studies in veterinary medicine, he followed a successful career in neurophysiological research. He was Research Associate (1961-1962) and Visiting Professor (1973-1976) at the Neurophysiology Department University of Wisconsin, USA. He was the first Director (1958-1960) of the Institute of Physiology at the Austral University, Valdivia, and was Professor (1963-1973; 1977-1994) and Chairman of the Department of Physiology and Biophysics, University of Chile, Santiago, Chile, where he led a group of researchers in auditory physiology, introduced the use of computer techniques to physiological studies, and developed several projects of applied neurophysiology.
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Biological research · Jan 2010
Correlations of recognition memory performance with expression and methylation of brain-derived neurotrophic factor in rats.
Object recognition memory allows discrimination between novel and familiar objects. This kind of memory consists of two components: recollection, which depends on the hippocampus, and familiarity, which depends on the perirhinal cortex (Pcx). The importance of brain-derived neurotrophic factor (BDNF) for recognition memory has already been recognized. ⋯ We found a significant correlation between performance on the novel object task and the expression of BDNF, negatively in hippocampal slices and positively in perirhinal cortical slices. By contrast, methylation of DNA in CpG island 1 in the promoter of exon 1 in BDNF only correlated in hippocampal slices, but not in the Pxc cortical slices from trained animals. These results suggest that DNA methylation may be involved in the regulation of the BDNF gene during recognition memory, at least in the hippocampus.