Naloxone influences retention behaviour depending on the degree of novelty inherent to the training situation

The effects of immediate posttraining subcutaneous administration of naloxone (0.25, 1 or 5 mg/kg) on retention behaviour of rats trained in an inhibitory avoidance task, subjected or not to familiarization with the training situation prior to the training trial (pretraining) have been investigated. Naloxone did not influence performance of pretrained rats not subjected to footshock at training. The drug did not significantly modify retention latencies of pretrained rats subjected to a weak footshock. However, administration of naloxone facilitated retention behaviour of non-pretrained rats subjected to a weak footshock. Likewise, naloxone significantly increases retention latencies of pretrained rats subjected to a high footshock at the training trial. These data indicate that naloxone influences retention behaviour depending on the degree of novelty linked to the training situation: a facilitatory effect of the drug is observed when the training trial becomes associated with a clear novel situation for the animals (high footshock in pretrained rats or a weak footshock in non-pretrained animals).     

Serial measurements of a plasma prostacyclin inhibitor in a patient with recurrent abortions and lupus anticoagulant; a case report

Defective plasmatic stimulation of prostacyclin (PGI2) production by vascular cells has been described in patients with lupus anticoagulant (LAC). A young woman with recurrent abortions, LAC and evidence for deficient PGI2 production was studied. Serial measurements of a plasma PGI2 inhibitor, LAC and anticardiolipin antibodies (ACA) have been performed before and throughout her fourth pregnancy. Antenatal care and treatment with prednisone and heparin started at 10 weeks gestation. The plasma of our patient continued to inhibit PGI2 production by vascular cells despite treatment. The presence of inhibitor(s) of PGI2 release was confirmed by mixing the patient's plasma with normal plasma. In addition, an IgM lupus anticoagulant fraction (but not the IgG fraction) interfered with the release of arachidonic acid in human endothelial cells induced by thrombin. Despite prednisone and heparin treatment we did not find a complete correction of the LAC activity and the ACA (IgM type) still remained positive before the detection of a fetal death at 26 weeks. The placenta showed abundant infarcts and areas of ischaemic necrosis. We suggest that the defect in vascular PGI2 release could compromise fetal outcome.     

Adrenocortical response to acute and chronic ethanol administration in rats

Acute ethanol administration (2 g/kg IP) induced a significant rise in serum corticosterone levels which seemed to be related to blood ethanol concentration. Chronic ethanol administration, in the form of a liquid diet for 16 or 30 days, did not alter the levels of serum corticosterone. Chronic treatment of rats with a liquid diet containing ethanol resulted in the development of tolerance.     

Role of arachidonic acid metabolism on corticotropin-releasing factor (CRF)-release induced by interleukin-1 from superfused rat hypothalami.

The present work shows that the corticotropin-releasing factor (CRF)-releasing activity of interleukin-1 (IL-1) is partially inhibited by a phospholipase A2 (mepacrine) or a cyclooxygenase (indomethacin) inhibitor, but is not affected by inhibition of the lypoxygenase pathway with norhydroguaiaretic acid. These results indicate that the metabolism of arachidonic acid plays an important role as mediator of the effects of IL-1 on CRF release. It is also shown that products of the cyclooxygenase activity such as prostaglandins can stimulate CRF secretion by a direct action on the hypothalamus. Whereas PGE2 failed to induce increases on CRF release, PGF2 alpha stimulated in a dose-dependent manner (21-340 nM), the CRF release from continuous perifused hypothalami. It is suggested that PGF2 alpha could be involved as a messenger in the hypothalamic CRF secretion induced by IL-1.     

Effects of acute and prolonged administration of chlordiazepoxide upon the pituitary-adrenal activity and brain catecholamines in sound stressed and unstressed rats

We have studied the effects of chlordiazepoxide upon the pituitary-adrenal activity (evaluated by the levels of serum corticosterone), and brain catecholamines in rats exposed to sound stimulation of 500 cycles per second at 110 decibels for 15 min. The sound stimulus itself induced a 3-fold rise in the serum corticosterone level. Acute administration of chlordiazepoxide to rats not subjected to sound stimulation induced significant increases in serum corticosterone levels; this effect was dose-dependent in the dose range of 5 to 25 mg/kg. An inhibition of the stress response was observed in rats injected acutely with the drug in doses ranging from 5 to 15 mg/kg and subjected to sound stimulation. Development of tolerance to the acute effects of the drug on the pituitary-adrenal activity was observed. Brain dopamine and noradrenaline levels showed a significant decrease after acute administration of some of the drug doses, but a dose-related effect was never observed. Prolonged treatment with chlordiazepoxide does not significantly affect the levels of either dopamine or noradrenaline at any duration of treatment.The results point to the possibility that the sites in the central nervous system mediating the depressant action of chlordiazepoxide and those mediating the anxiolytic action influence the pituitary-adrenal activity in an opposite fashion: the depressant in a stimulatory way and the anxiolytic in an inhibitory way. However, the mechanisms of tolerance development to the stimulatory or inhibitory action of chlordiazepoxide on the pituitary-adrenal activity seem to be alike.     

Naloxone decreases ethanol consumption within a free choice paradigm in rats

The effect of subcutaneous naloxone administration on the consumption of a weak ethanol solution in rats on the three consecutive days (testing days) was investigated using a behavioral paradigm which includes a first forced ethanol exposure (conditioning day) followed by a two-bottle ethanol/water choice procedure. Besides reducing fluid intake, naloxone treatment prior to forced ethanol exposure interferes with the acquisition of ethanol preference. Post-conditioning naloxone administration fails to affect ethanol preference. Administration of naloxone prior to the first testing session induces a reduction on total fluid intake, at the day of treatment; a decrease on ethanol preference throughout the three consecutive testing days is also observed with the higher dose of the antagonist (5 mg/kg). An involvement of endogenous opioids in ethanol consumption is suggested through the modulation of alcohol reinforcement or the affective quality of the gustatory cue.     

Chronic administration of morphine in cats: effects on adrenal and urinary catecholamines.

Adrenaline and noradrenaline levels in the adrenal glands and the excretion of both bioamines in urine of adult cats were investigated after chronic administration of morphine and nalorphine-induced withdrawal. After 7 days of daily consecutive morphine treatment, a significant increase in the adrenal noradrenaline content and a drop in adrenaline content were observed. After 2 weeks of daily injection of morphine, no significant changes were observed in the adrenal catecholamine level. One month of treatment with the opioid caused a significant increase in the adrenal content of both adrenaline and noradrenaline. Urinary excretion of catecholamines was significantly increased during the 4 weeks of treatment. In animals subjected to spontaneous or induced withdrawal with nalorphine, the adrenal content of catecholamines was altered and the ratio adrenaline/noradrenaline in the adrenal gland was shifted towards noradrenaline. A first injection of morphine produced an excitant manic response characterized by hyperexcitement and aggressive behaviour; animals chronically treated with the drug showed a progressively diminished response to this effect of the drug. It is concluded that physical dependence on morphine is reached by cats chronically treated with morphine and that this effect of the drug influences adrenomedulllary function in a different fashion depending on the stage of morphine treatment.     

Socioeconomic disadvantage and periodontal disease: the Dental Atherosclerosis Risk in Communities study

OBJECTIVES: We used data from the Dental Atherosclerosis Risk in Communities study to examine whether individual- and neighborhood-level socioeconomic characteristics were associated with periodontal disease. METHODS: We assessed severe periodontitis with a combination of clinical attachment loss and pocket depth measures. Marginal logistic regression modeling was used to estimate the association between individual and neighborhood socioeconomic indicators and prevalence of severe periodontitis before and after control for selected covariates. Residual intraneighborhood correlations in outcomes were taken into account in the analyses. RESULTS: Individual-level income and education were associated with severe periodontitis among Whites and African Americans, and these associations remained significant after adjustment for age, gender, recruitment center, and neighborhood socioeconomic score. Low-income Whites residing in disadvantaged neighborhoods had 1.8-fold (95% confidence interval=1.2, 2.7) higher odds of having severe periodontitis than high-income Whites residing in advantaged neighborhoods. CONCLUSIONS: Individual income and education were associated with severe periodontitis independently of neighborhood socioeconomic circumstances. Although the association between neighborhood socioeconomic status and severe periodontitis was not statistically significant, poverty and residence in a disadvantaged neighborhood were associated with higher odds of severe periodontitis among Whites.     

Analysis of the formulation of policies on aging in plans for social and health care and care of the elderly in autonomous communities in Spain

OBJECTIVE: To describe and compare the formulation of policies on aging in the autonomous communities of Spain available in 2002. MATERIAL AND METHOD: The formulation of policies on aging in autonomous communities that published a specific plan on the care of the elderly or a social and health care plan that included elderly care were compared with a standard. RESULTS: In 2002, seven autonomous communities had a document with the above-mentioned characteristics. Six of these were social and health care plans that included a specific section on the care of the elderly; the Canary Islands had a plan for the care of the elderly in primary care. Differences were found in the number of interventions proposed by each autonomous community, ranging between 14 (Catalonia) and 44 (Cantabria) out of the 62 proposed in the standard. Cantabria and Extremadura were the only autonomous communities that established interventions in all the possible areas. Wide variability was found in the plans, depending on their orientation toward an individual and treatment focus (Extremadura) or toward a social and preventive focus (Cantabria). CONCLUSIONS: The number of proposals in the various plans was lower that that in the standard used for comparison. In general, the plans focused on the later phases of dependency and on the immediate setting of the elderly.     

Adrenomedullary responses to acute and chronic ethanol administration to rats

The variations in levels of adrenal dopamine (DA), noradrenaline (NA) and adrenaline (A) after acute and chronic ethanol administration have been studied in rats. A relatively moderate dose of ethanol (2 g/kg) induced significant increases in DA levels, while NA and A concentrations did not change, or decreased depending on the interval of time elapsed after ethanol injection. These findings, together with those obtained in rats pretreated with alpha-methyl-p-tyrosine methyl ester (AMT), indicate an increased turnover of adrenal catecholamines (CA) after acute ethanol treatment. Chronic ethanol intake leads to significant increases in DA levels in the adrenal glands of rats subjected to ethanol feeding for 12 and 16 days; no changes were observed in NA or A concentrations in these groups of animals. After 30 days of ethanol ingestion, the levels of the three CA are within the control range, a fact that could suggest some adaptation of the sympatho-adrenal system to ethanol. After 16 days of treatment, tolerance to acute effects of ethanol on adrenomedullary system was not clear.