Search results for " DOP"
showing 10 items of 770 documents
Role of dopamine neurotransmission in the long-term effects of repeated social defeat on the conditioned rewarding effects of cocaine
2016
Numerous studies report that social defeat stress alters dopamine (DA) neurotransmission in several areas of the brain. Alterations of the mesolimbic dopaminergic pathway are believed to be responsible for the increased vulnerability to drug use observed as a result of social stress. In the present study, we evaluated the influence of DA receptors on the long-term effect of repeated social defeat (RSD) on the conditioned rewarding and reinstating effects of cocaine. For this purpose, the D1R antagonist SCH 23390 and the D1R antagonist raclopride were administered 30 min before each social defeat and a cocaine-induced CPP procedure was initiated three weeks later. The expression of the D1R a…
Impact of insulin resistance on cardiac and vascular function.
2016
Background Insulin resistance (IR), constitutes an important cardiovascular risk factor and can cause ischemic heart disease. It can lead to left ventricular dysfunction with a mechanism independent of ischemic heart disease and it is closely associated with impaired vascular function. The aim of our study was to explore the impact of IR on cardiac and vascular function, in patients with cardiovascular risk factors but angiographically undamaged coronary arteries. Methods We studied 32 patients (62.06 ± 11.19 years) with cardiovascular risk factors. All patients underwent coronary angiography, echocardiography, Doppler ultrasound of carotid arteries and laboratory tests. Exclusion criteria …
Dopamine acting through D2 receptors modulates the expression of PSA-NCAM, a molecule related to neuronal structural plasticity, in the medial prefro…
2008
A "neuroplastic" hypothesis proposes that changes in neuronal structural plasticity may underlie the aetiology of depression and the action of antidepressants. The medial prefrontal cortex (mPFC) is affected by this disorder and shows an intense expression of the polysialylated form of the neural cell adhesion molecule (PSA-NCAM), a plasticity-associated molecule, which is expressed mainly in interneurons. The monoamines serotonin, dopamine and noradrenaline are the principal targets of antidepressant action. Pharmacological manipulation of serotonin levels regulates synaptophysin and PSA-NCAM expression in the adult mPFC. However, the involvement of structural plasticity on the antidepress…
On the number of measurement sites required to assess regional cerebral blood flow by laser-Doppler scanning during cerebral ischemia and reperfusion.
2001
The aim of this study was to determine whether the number of measurement sites affected the precision of regional cerebral blood flow (CBF) assessment by Laser-Doppler (LD). A simulation study was applied based on data obtained by scanning the cortex in 25 rats during baseline conditions, 15 min global cerebral ischemia and reperfusion. Random samples were repeatedly collected from 1 to 100 locations and deviations from the median of the entire CBF data pool (800 locations) were determined. Single location CBF measurements missed the true median by 24.8+/-2.2 LD-units (baseline conditions, n=100 simulations, mean+/-SEM), 2.7+/-0.6 LD-units (ischemia), and 31.9+/-2.4 LD-units (30th min reper…
A genetic variant of the atrial natriuretic peptide gene is associated with cardiometabolic protection in the general community
2011
Objectives We sought to define the cardiometabolic phenotype associated with rs5068, a genetic variant of the atrial natriuretic peptide (ANP) gene. Background The ANP and B-type natriuretic peptide play an important role in cardiorenal homeostasis but also exert metabolic actions. Methods We genotyped 1,608 randomly selected residents from Olmsted County, Minnesota. Subjects were well-characterized. Results Genotype frequencies were: AA 89.9%, AG 9.7%, and GG 0.4%; all subsequent analyses were AA versus AG+GG. The G allele was associated with increased plasma levels of N-terminal pro-atrial natriuretic peptide (p = 0.002), after adjustment for age and sex. The minor allele was also associa…
Hippocampal dopamine receptors modulate the motor activation and the increase in dopamine levels in the rat nucleus accumbens evoked by chemical stim…
2005
A number of studies have shown that chemical stimulation (using N-methyl-D-aspartate (NMDA) infusions) or electrical stimulation of the ventral hippocampus (VH) elicits locomotor activation and sustained increases in nucleus accumbens (NAc) dopamine (DA) levels in rodents. How DA neurotransmission in NAc is involved in these effects has also been well established. However, the modulatory role of the DA receptors located in VH is not yet fully understood. The purpose of this study was to characterize the role played by VH D1 and D2 subtype receptors in both the locomotor activation and NAc DA increases induced by NMDA stimulation of the VH. This was assessed by studying how retrodialysis app…
Hippocampal dopamine receptors modulate cFos expression in the rat nucleus accumbens evoked by chemical stimulation of the ventral hippocampus
2005
Recently, we have shown that D1 and D2 receptors in the ventral hippocampus (VH) modulate both the locomotor activation and the increase in dopamine (DA) levels in the rat nucleus accumbens (NAc) induced by NMDA stimulation of the VH. In the present study we analyze the possible role of VH D1 and D2 receptors in the modulation of the cFos expression in NAc (core and shell subregions) and in dorsal striatum. This was assessed by immunohistochemical analysis of cFos expression in the rat brains after retro-dialysis application of NMDA (50mM, 10 min) into VH, in absence and in presence of either the D1/D5 receptor antagonist SCH 23390 (100 and 250 microM, 60 min) or the D2 receptor antagonist …
Color Doppler ultrasonography in pediatric intussusception.
1994
CDU was used in 11 children with intussusception. Demonstration of vascular images within the "pseudokidney" mass was possible in none of 11 cases. Of them, eight could be treated by hydrostatic reduction. In the remaining case, marked edema of the bowel wall did not allow reduction, and surgery had to be performed: no necrosis was observed in the surgical specimen. Both patients in whom CDU failed to demonstrate vascular signals had necrosis at surgery, and bowel resection was performed. Because of the limited number of patients examined at this time, no firm conclusions can be drawn from our experience. However, CDU seems a promising technique in detecting vascular changes occurring in in…
Capillary flow and diameter changes during reperfusion after global cerebral ischemia studied by intravital video microscopy.
2004
The reaction of cerebral capillaries to ischemia is unclear. Based on Hossmann's observation of postischemic “delayed hypoperfusion,” we hypothesized that capillary flow is decreased during reperfusion because of increased precapillary flow resistance. To test this hypothesis, we measured cerebral capillary erythrocyte velocity and diameter changes by intravital microscopy in gerbils. A cranial window was prepared over the frontoparietal cortex in 26 gerbils anesthetized with halothane. The animals underwent either a sham operation or fifteen minutes of bilateral carotid artery occlusion causing global cerebral ischemia. Capillary flow velocities were measured by frame-to-frame tracking of…
Impaired cerebrovascular autoregulation in patients with severe sepsis and sepsis-associated delirium
2012
Introduction Sepsis-associated delirium (SAD) increases morbidity in septic patients and, therefore, factors contributing to SAD should be further characterized. One possible mechanism might be the impairment of cerebrovascular autoregulation (AR) by sepsis, leading to cerebral hypo- or hyperperfusion in these haemodynamically unstable patients. Therefore, the present study investigates the relationship between the incidence of SAD and the status of AR during sepsis. Methods Cerebral blood flow velocity was measured using transcranial Doppler sonography and was correlated with the invasive arterial blood pressure curve to calculate the index of AR Mx (Mx>0.3 indicates impaired AR). Mx was m…