IFN-gamma production of adult rat astrocytes triggered by TNF-alpha

IFN-gamma plays an important role in modulating inflammatory responses within the CNS. The cell type responsible for IFN-gamma production within the CNS is less well defined. We examined the production and regulation of IFN-gamma by adult rat astrocytes. IFN-gamma was hardly detectable in cultured astrocytes, while addition of TNF-alpha dose-dependently induced IFN-gamma production by astrocytes. No IFN-gamma production by astrocytes could be induced by LPS, IL-10 or TGF-beta 1. TNF-alpha-induced IFN-gamma production by astrocytes was inhibited by treatment of astrocytes with TGF-beta 1, but not IL-10. TNF-alpha induced IFN-gamma production by astrocytes was confirmed by using immunocytochemical staining. The data suggest that astrocyte-derived IFN-gamma induced by TNF-alpha may participate in local immune reactions of the brain in an autocrine and paracrine fashion.     

Selective effects on CRF neurons and catecholamine terminals in two stress-responsive regions of adult rat brain after prenatal exposure to diazepam

Earlier work demonstrated that prenatal exposure to diazepam (DZ) selectively affected the noradrenergic (NE) terminals in the hypothalamus, leading to decreased basal NE levels, turnover rate, and release in adult offspring as well as altered responses to stressors in these NE projections. The exposure also affected plasma hormonal responses to stressors. In the present work, we used immunocytochemistry to study the effects of prenatal DZ exposure on NE terminals and on corticotropin-releasing factor (CRF)-containing neurons in the paraventricular nucleus (PVN) of the hypothalamus. DZ exposure (2.5 or 10 mg/kg over gestational days 14-20) led to a decrease in dopamine-beta-hydroxylase (DBH)-immunoreactivity (-ir) and a decrease in CRF-ir containing cells within the PVN of adult rats. The exposure also decreased DBH-ir in the ventral portion of the bed nucleus of the stria terminalis (BNST) but did not affect CRF-ir in the oval nucleus of BNST. Therefore, this study provides anatomic evidence that targeting benzodiazepine binding sites prenatally affects two neurotransmitter systems involved in responses to stressors.     

The effect of diazepam on voluntary ethanol intake in a rat model of alcoholism

The neuropharmacological study of serotonin and behavior has followed two fundamentally different strategies. One approach has used behavior as a dependent variable for assaying drug effects. To characterize serotonergic drugs, most studies have used relatively simple behaviors, such as locomotor activity, startle, exploration, operant responses, and sleep. A second approach has focused on behavior, with drugs used as tools to elucidate the physiological role of serotonin. These studies have increasingly focused on behaviors of ethological importance, including aggression, sexual behavior, and other forms of social interaction. Here we review studies using this approach to focus on one particular kind of social interaction: affiliation.     

Consequences of prenatal morphine exposure on the hypothalamo-pituitary-adrenal axis in the newborn rat: effect of maternal adrenalectomy

The hypothalamo-pituitary-adrenal axis is already functional in rat fetuses in late gestation. We have reported previously that prenatal morphine exposure induced a severe atrophy of the adrenals and a decrease of corticosterone release in newborn rats at birth and during the early postnatal period. The first aim of the present study was to determine the effects of prenatal morphine exposure (1) on corticotrophin releasing factor (CRF) content of the hypothalamus, CRF immunofluorescence in the median eminence, CRF mRNA in the paraventricular nucleus (PVN) and pro-opiomelanocortin (POMC) mRNA in the anterior pituitary gland; (2) on CRF-induced ACTH release from the anterior pituitary gland in vitro; and (3) on ACTH-induced corticosterone release by the adrenals in vitro. Moreover, as morphine is a hepatotoxic factor, we determined the effects of prenatal morphine on liver weight and plasma corticosteroid binding globulin (CBG) binding capacity in newborn rats. Since acute administration of morphine stimulates corticosterone secretion in adult rats and since maternal corticosterone can cross the placental barrier, we also measured both adrenal weight and glucocorticoid activity in newborns from adrenalectomized mothers treated with morphine. The present results show that prenatal morphine given to intact mothers induced adrenal atrophy and hypoactivity in newborns but did not affect the responsiveness of the anterior pituitary gland to CRF or that of the adrenal gland to ACTH. Prenatal morphine reduced both CRF content in the newborn hypothalamus and CRF immunofluorescence in the median eminence without a significant effect on CRF mRNA expression in the PVN. Moreover, morphine induced a significant decrease of POMC mRNA in the anterior pituitary gland. However, morphine did not significantly affect the weight of the liver, or the plasma CBG binding capacity for corticosterone, in rat pups. In contrast, morphine treatment of the adrenalectomized mothers did not induce adrenal atrophy in newborns and did not impair adrenal activation during the early postnatal period. Maternal adrenalectomy also prevented the effects of prenatal morphine on hypothalamic content of CRF, CRF immunofluorescence in the median eminence, and POMC mRNA in the anterior pituitary gland. However, adrenal atrophy was observed at term in newborns of adrenalectomized mothers treated with both morphine and corticosterone or only corticosterone. In conclusion, morphine given to pregnant rats induced inhibition of the hypothalamo-pituitary-adrenal axis in pups at term. As maternal adrenalectomy prevented these effects, we speculate that an adrenal factor of maternal origin, probably corticosterone, mediated these drug effects on newborns.     

Effect of prenatal exposure to ethanol on intestinal development of rat fetuses

BACKGROUND: Chronic alcoholism in pregnant animals and humans lead to general growth impairment in their offspring, which show multiple birth defects and delayed grown (fetal alcohol syndrome). Here we study the maturation of the intestine under the effect of chronic exposure to ethanol in utero together with associated malnutrition. METHODS: Lactase, acid beta-galactosidase, maltase, and alkaline phosphatase activity profiles were monitored in 18-, 19-, 20-, and 21-day-old fetuses from rats kept under three nutritional treatments before and during gestation: alcohol-treated (25% ethanol in drinking water), fiber-treated (50% cellulose-diluted diet) as a control of the malnutrition associated with chronic alcoholism, and control or normal diet. Serum corticosterone determination and lactase immunolocalization were carried out. To detect possible direct effects of ethanol during the period of mucosa development, intestinal explants from 18-, 19-, and 20-day-old control fetuses were cultured either in the basal medium alone or in a medium containing 25 mM ethanol for 72, 48, and 24 h of incubation, respectively. RESULTS: Following chronic ethanol exposure in utero, intestinal weight and brush-border protein content and the specific activities of lactase, acid beta-galactosidase, maltase, and alkaline phosphatase were significantly lower than those of nutritional controls. Organ culture results, under the assay conditions stated, did not show a direct effect of ethanol 25 mM on prenatal mucosal functionality. CONCLUSIONS: All these results suggest that maternal malnutrition is not primarily responsible for the impaired intestinal maturation in rat fetuses from alcohol-treated mothers; indirect effects of ethanol and/or its derivatives throughout embryo-fetal development could be necessary to promote this intestinal delay.     

The neuropeptide calcitonin gene-related peptide inhibits TNF-alpha but poorly induces IL-6 production by fetal rat osteoblasts

Tumour necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) are potent inflammatory cytokines produced by osteoblasts and whose contribution to bone loss occurring in oestrogen deficiency is well documented. Calcitonin gene-related peptide (CGRP) is a neuropeptide abundantly concentrated in sensory nerve endings innervating bone metaphyses and periosteum suggesting that it controls bone homeostasis locally. Since CGRP was shown to inhibit TNF-alpha production by T cells and stimulate IL-6 expression by fibroblasts, this study was designed to investigate whether CGRP regulated TNF-alpha and IL-6 production by osteoblasts. We show that CGRP inhibits the production of TNF-alpha by both lipopolysaccharide (LPS)- and IL-1-stimulated fetal rat osteoblasts. Like CGRP, the cAMP agonists prostaglandin E2 (PGE2), dibutyryl cAMP (Bt2cAMP) and forskolin inhibit TNF-alpha production by osteoblasts. Exposure of osteoblasts to a high dose of phorbol myristoyl acetate (PMA) to deplete PKC activity abolished CGRP-mediated TNF-alpha suppression. In contrast with its potent inhibition of TNF-alpha production, we show that CGRP is a weak inducer of IL-6 when compared to PGE2, Bt2cAMP and forskolin. However, in presence of isobutylmethylxanthine (IBMX) CGRP stimulates the production of IL-6. Collectively, these data suggest that the inhibition of TNF-alpha CGRP is cAMP dependent and PMA sensitive and that the concentration of intracellular cAMP may be a regulatory mechanism for IL-6 expression in osteoblasts.     

Developmental and behavioral effects of prenatal primidone exposure in the rat

Pregnant Sprague-Dawley rats were administered primidone (PRM) by oral gavage on gestation days 8-17 in doses of 0.40, and 80 mg/kg. Although these doses of PRM did not produce significant differences in litter size, birth weight, mortality, date of attainment of developmental landmarks or measures of preweaning reflex and motor development, there were a number of significant differences that developed as the animals approached and entered adulthood. When tested as adults, the 80 mg/kg male rats showed a deficit in the performance of an eight-arm radial maze task. These same animals showed a significant reduction in open field activity when tested as adults. In addition, both male and female PRM-treated animals showed reduced body weights at different periods corresponding to onset of sexual maturation during development. These findings are consistent with the larger body of literature reporting on the neurobehavioral teratology of phenobarbital, including its ability to produce lesions in the hippocampus and endocrine dysfunction resulting in reproductive deficits. These results suggest that PRM produces its adverse effects as a result of its metabolism to phenobarbital, which in turn affects the limbic system.     

Expression of p53 and ALZ-50 immunoreactivity in rat cortex: effect of prenatal exposure to ethanol

Neuronal death is an active process that results in the upregulation of antigens recognized by ALZ-50 and p53. Since prenatal exposure to ethanol can induce the postnatal death of cortical neurons, we examined the effects of ethanol on the in vivo expression of both the ALZ-50-positive antigen and p53. Pregnant rats were fed one of three diets, a liquid diet containing ethanol (Et), an isocaloric and isonutritive diet (Ct), or chow and water (Ch). Segments of frontoparietal cortex from fetuses and pups were examined for ethanol-induced changes (a) in the expression of ALZ-50 and p53 immunoreactivity using a quantitative immunoblotting assay and (b) in the distribution of ALZ-50- and p53-positive cells using immunohistochemistry. In control rats, ALZ-50 identified a 56-kDa peptide that was transiently expressed postnatally and peak expression occurred on postnatal day (P) 6 to P12. In Et-treated rats, peak expression was attained earlier (on P3) and was about three times of that achieved in the controls. The anti-p53 antibody identified three proteins (28, 56, and 58 kDa). Peak expression in control rats occurred during the second postnatal week and only the 58-kDa protein was expressed in appreciable amounts in adult cortex. Each p53-positive protein was affected by ethanol exposure. The 28- and 56-kDa p53-positive proteins were affected by ethanol much in the same way as was the ALZ-50-positive antigen. That is, the timing and amount of peak expression were earlier and lower, respectively, in the Et-treated rats. The postnatal expression of the 58-kDa protein was halved following prenatal exposure to ethanol. Both ALZ-50 and anti-p53 immunoprecipitated proteins are p53- and ALZ-50-positive, respectively. Thus, ethanol alters the expression of the ALZ-50- and p53-positive proteins and presumably the timing of neuronal death in the developing cortex. The parallel effects of prenatal ethanol exposure on the 56-kDa ALZ-50-positive antigen and the 28- and 56-kDa p53-positive proteins and the coprecipitation of the proteins are consistent with the notion that ALZ-50 recognizes a form of p53.     

Effects of prenatal alcohol exposure on the postnatal morphology of the rat oculomotor nucleus

Morphological development of the rat oculomotor nucleus was investigated on postnatal day 15 following a prenatal ethanol exposure. Analysis of toluidine blue stained plastic sections showed that the prenatal alcohol exposure caused a decrease in the density of neurons and an increase in the density of astrocytes in the center of the nucleus. There was an alcohol-induced reduction in the overall size of the cross-sectional region of the oculomotor nucleus, but no effect on the number of neurons per unit area of that total oculomotor region, indicating a delay or alteration of the migration of neurons to their normal clustered position in the center of the nucleus. The areas of the neuronal cell nucleus and nucleolus were not affected by the alcohol exposure. Analysis of Golgi-Cox-impregnated multipolar neurons showed that the alcohol exposure caused a reduction in area of the cell soma; a reduction in the number of dendritic branches; and a reduction in the complexity of the dendritic arbor relative to distance from the soma, based on concentric ring analysis. The results of this study demonstrate that gestational alcohol exposure can retard the maturation of the oculomotor nucleus.     

Cholera toxin increases IL-6 synthesis and decreases TNF-alpha production by rat peritoneal mast cells

Mast cells have been traditionally associated with an acute allergic response. However, their role in regulating chronic inflammatory processes must also be considered in view of evidence that mast cells synthesize and release a number of cytokines. In this study, we have examined the effect of cholera toxin (CT) on peritoneal mast cell IL-6 and TNF-alpha production. Highly purified, freshly isolated, rat peritoneal mast cells from Brown Norway rats were cultured in the presence of CT or its B subunit (CTB) alone or in combination with anti-IgE or bacterial LPS. Histamine release was measured after 10 min; IL-16 and TNF-alpha production was assessed in supernatants after 18 h. We found that CT or CTB alone did not affect histamine release; however, mast cell IL-6 production was significantly enhanced by CT but not by CTB. In contrast, constitutive production of TNF-alpha was inhibited by CT. The effects of CT were similar to our previous observations of the actions of prostaglandin E2 on mast cells. We also examined the effects of CT in combination with other mast cell activating agents. CT had no significant effect on anti-IgE-induced histamine release. An additive effect on IL-6 production was observed in the context of LPS. Forskolin, an agent known to increase intracellular cAMP levels, also induced a significant increase in IL-6 production, whereas TNF-alpha production was decreased. These data have important implications for our understanding of the regulation of mast cell cytokine production and the effects of CT on local cytokine production.     

Effects of prenatal ethanol exposure on parvalbumin-expressing GABAergic neurons in the adult rat medial septum

Exposure of human fetuses to ethanol often results in the fetal alcohol syndrome. Animal models of fetal alcohol syndrome have been developed and used to examine the consequences of prenatal ethanol exposure on the central nervous system. The objective of this study was to determine the long-term effects of prenatal ethanol exposure on parvalbumin-expressing (PA+) GABAergic neurons of the rat medial septum. Pregnant Long-Evans rats were maintained on 1 of 3 diets from gestational day 0 to 21: an ethanol-containing liquid diet in which ethanol accounted for 35% of the total calories, a similar diet with the isocaloric substitution of sucrose for ethanol, or a lab chow control diet. Offspring were killed on postnatal day 60, and their brains were prepared for parvalbumin immunocytochemistry. Female rats exposed to the ethanol-containing diet during gestation had 42% fewer PA+ neurons in the medial septum and reduced PA+ cell density when compared with female rats exposed to the sucrose diet. Ethanol females also had fewer PA+ neurons per unit volume than sucrose females. Male rats exposed to ethanol did not display a similar reduction in PA+ neurons or density. No effect of prenatal diet was found on the area or volume of the medial septum, nor were cell diameters affected. As such, prenatal exposure to ethanol seems to reduce permanently the number of PA+ neurons in the female rat medical septum without affecting area, volume, or neuronal size. Functional implications and possible relations to the fetal alcohol syndrome are discussed.     

Regulation of TNF-alpha production in activated mouse macrophages by progesterone

The purpose of this study was to investigate the relationships between macrophage production of TNF-alpha and female hormones. Northern blot hybridization experiments showed that the female sex steroid hormone, progesterone, decreases steady state levels of TNF-alpha mRNA in LPS-activated mouse macrophages (RAW 264.7 and ANA-1 cells) in vitro. The production of intracellular and secreted TNF-alpha protein, as determined by ELISA, was decreased in both progesterone- and dexamethasone-treated, LPS-stimulated macrophages. Estrogen had no effect on expression of the TNF-alpha gene in mouse macrophages and did not alter progesterone-mediated suppression. Additional experiments conducted to investigate the mechanism of action of progesterone showed that this hormone, like dexamethasone, elevates steady state mRNA levels of IkappaB alpha and increases the levels of IkappaB alpha protein that are translocated from the cytoplasm to the nucleus. Thus, progesterone is a potent inhibitor of steady state levels TNF-alpha mRNA and TNF-alpha protein production in activated macrophages and may achieve this result through effects on an inhibitor of NF-kappaB.     

Effect of prenatal and postnatal exposure to ethanol on rat central nervous system gangliosides and glycosidases

We investigated the effect of maternal alcohol consumption on cell number, gangliosides and ganglioside catabolizing enzymes in the central nervous system (CNS) of the offspring. Virgin female rats of the Charles Foster strain were given 15% (v/v) ethanol in drinking water one month prior to conception and during gestation and lactation. At 21 days postnatal age, the offspring were sacrificed and the brains were separated into cerebrum, cerebellum and brain stem to investigate possible regional variations. Compared to controls, wet weight of cerebrum, cerebellum and brain stem, and of spinal cord was decreased in the pups exposed to alcohol. DNA and protein contents were also found to be lowered in all the CNS regions of the pups exposed to alcohol. Conversely, maternal alcohol consumption was found to increase the concentration and the content of total ganglioside N-acetyl-neuraminic (NANA) in CNS of the pups. In addition, alcohol treatment was found to induce alterations in the proportions of individual ganglioside fractions. Interestingly, these alterations are somewhat different than those observed in the neonatal brain and spinal cord of the pups subjected to prenatal alcohol exposure. The alterations in the proportions of ganglioside fractions were shown to be region-specific. Maternal alcohol consumption resulted in decreased activities of sialidase, beta-galactosidase, beta-glucosidase and beta-hexosaminidase. The results suggest that the alcohol-associated increases in ganglioside concentration may be at least partly due to the decreased activities of ganglioside catabolizing enzymes.     

Regulation of nitric oxide production by rat alveolar macrophages in response to silica exposure

Research conducted primarily over the past 5-8 years on the psychosocial effects of pediatric chronic physical disorders on children and their families is reviewed. A large body of studies show that both children and their mothers, as groups, are at increased risk for psychosocial adjustment problems compared to peers, but that there is considerable individual variation in outcome. Since the last review on this topic (Eiser, 1990a), many studies have been conducted to identify risk and resistance factors associated with differences in adjustment among these children and their mothers. Improvements are noted in the theoretical basis for this work, programmatic nature of some of the research, and efforts at producing clinically relevant information. Evaluations of interventions, however, are lagging. Critical issues and future directions regarding developmental approaches, theory, method, measurement, and intervention are discussed.     

Role of central mu-opioid receptors in the modulation of nitric oxide production by splenocytes

Previous studies have shown that administration of morphine results in alterations of splenic macrophage nitric oxide production. The present studies were conducted to determine the subtype of opioid receptor involved in the modulation of macrophage nitric oxide production. Moreover, the present work was directed at determining whether nitric oxide production is regulated through opioid receptors in the central nervous system (CNS) or via opioid receptors found directly on splenocytes. The study shows that intracerebroventricular (i.c.v.) administration of the mu-selective opioid agonist, DAMGO, to rats dose-dependently increases the production of nitric oxide by splenocytes stimulated with toxic shock syndrome toxin (TSST-1). The effect of DAMGO is blocked by prior i.c.v. administration of N-methylnaltrexone. In contrast, i.c.v. administration of the kappa-selective agonist, U69,593, and the delta-selective agonist, DPDPE, have no significant effect on the production of nitric oxide. Furthermore, the in vitro administration of DAMGO, DPDPE, or U69,593 to splenocytes cultures does not significantly alter the production of nitric oxide by splenocytes. In addition, the present work shows that elevation of nitric oxide production by i.c.v. administration of DAMGO produces functional changes in splenic lymphocytes. Collectively, these results indicate that mu-opioid receptors within the CNS are involved in the regulation of splenic nitric oxide production.     

The effect of expanding Medicaid prenatal services on birth outcomes

OBJECTIVES: Over 80% of US states have implemented expansions in prenatal services for Medicaid-enrolled women, including case management, nutritional and psychosocial counseling, health education, and home visiting. This study evaluates the effect of Washington State's expansion of such services on prenatal care use and low-birthweight rates. METHODS: The change in prenatal care use and low-birthweight rates among Washington's Medicaid-enrolled pregnant women before and after initiation of expanded prenatal services was compared with the change in these outcomes in Colorado, a control state. RESULTS: The percentage of expected prenatal visits completed increased significantly, from 84% to 87%, in both states. Washington's low-birthweight rate decreased (7.1% to 6.4%, P = .12), while Colorado's rate increased slightly (10.4% to 10.6%, P = .74). Washington's improvement was largely due to decreases in low-birthweight rates for medically high-risk women (18.0% to 13.7%, P = .01, for adults; 22.5% to 11.5%, P = .03, for teenagers), especially those with preexisting medical conditions. CONCLUSIONS: A statewide Medicaid-sponsored support service and case management program was associated with a decrease in the low-birthweight rate of medically high-risk women.     

The effects of prenatal exposure to cocaine on the dopaminergic cells in the rat retina. An immunocytochemical and neurochemical study

5-Hydroxytryptamine1A (5-HT1A) receptors have been visualized at the electron microscopic level in selected areas (dorsal raphe nucleus, hippocampus, septum) of the rat brain using specific anti-peptide antibodies. 5-HT1A receptor immunoreactivity was found almost exclusively in the somatodendritic compartment of neurons and was very rarely observed within processes possibly belonging to glial cells. The immunoenzymatic reaction product was associated exclusively with dendritic spines in the dorsal hippocampus, whereas in the dorsal raphe nucleus and the septal complex, immunoreactivity was found in both dendritic processes and somata. Although some immunolabeling was observed within the cytoplasm of cell bodies, 5-HT1A receptor immunoreactivity was essentially confined to the plasma membrane where it was unevenly distributed. It was frequently associated with synapses (except in the dorsal raphe nucleus), but was also found extrasynaptically in both somata and dendrites. These data suggest that the action of serotonin via 5-HT1A receptor could occur through junctional as well as nonjunctional transmission.     

Adverse consequences of prenatal illicit drug exposure

Our appreciation of the impact on health of illicit drug use is growing. Once considered a maternal risk, prenatal drug exposure may target fetal neurobehavior, affecting attention and learning as the child grows into adulthood. Cocaine, opiates, marijuana, and amphetamines have each been scrutinized for adverse actions on placental transport, fetal behavior states, newborn withdrawal, and childhood learning and attentive skills. Neurotransmitter analysis in the animal model after prenatal drug exposure now provides biological support for these clinical findings. The increasing prevalence of drug use by pregnant women, the effect of illicit drug use on transmission of the human immunodeficiency virus, and the maternal and fetal consequences of illicit drug exposure make illicit drug use in pregnancy a central challenge in maternal-fetal medicine and a need-to-know field in general obstetrics.     

Inhibitory effect of albumin-derived advanced glycosylation products on PMA-induced superoxide anion production by rat macrophages

Advanced glycosylation end products (AGE) are implicated in many of the complications of diabetes. In the same way, infectious diseases are frequently associated with this disease. An impaired respiratory burst in macrophages may be a cause of infectious complications in diabetic patients. To establish a possible mechanism of this altered cell function, we have analyzed the effect of AGE-modified proteins on PMA-dependent superoxide anion production (O2.-) from normal rat peritoneal macrophages. We have used AGE-modified bovine serum albumin (AGE-BSA) prepared by incubation with glucose. AGE-BSA partially inhibits the phorbol ester-dependent superoxide production by macrophages in vitro. The specificity of this inhibitory effect is demonstrated by the fact that aminoguanidine, an inhibitor of the formation of AGE products, fully prevents the effect of AGE-BSA in vitro. Macrophages from diabetic rats shown an inhibition on PMA dependent-O2.- production. However, the treatment in vivo with aminoguanidine produced a cancelation of the inhibitory effect observed in the diabetic state. These data suggest that AGE-modified proteins could be implicated in the impairment of macrophage respiratory burst in diabetes.