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PubMed1990

Effect of prenatal exposure to phencyclidine on the postnatal development of the cholinergic system in the rat.

The purpose of this study was to examine the effect of prenatal exposure to phencyclidine (PCP) on the postnatal development of the cholinergic system in the neostriatum and the neocortex. Pregnant females were injected daily with PCP (0.5 mg/kg s.c.) from conception to parturition. On postnatal day 21 or 35, pups were injected with a challenge dose of PCP (0.5 mg/kg s.c.). The levels of acetylcholine and choline were measured, as well as the incorporation of deuterium-labelled choline into newly synthesized acetylcholine in the frontal cortex and neostriatum. The data demonstrate that even at 21 days, rat pups exposed to PCP in utero were more sensitive to a challenge dose of PCP than the saline controls. Thus, a tolerance to PCP, even after a prolonged prenatal exposure did not develop.

Acetylcholine↗
PubMed2005

[Stress-resistance of weedy rice Luolijing (Oryza sativa)].

Weedy rice Luolijing (Oryza sativa) is generated in Dandong, Liaoning Province of Northeast China. Its plant height is taller than normal planted rice varieties, and its caryopsis is medium or long in size, which dropped easily after matured. The color of the caryopsis shell is straw-like or yellow alternated with black-gray. The spikelet is with or without awns, and the length of the awns is 2-12 cm. The 1000 caryopsis weight is 23.5 g, and the hull is nacarat. The seed germination rate at 13-38 degrees C is > 88%. Under 2.5-10 cm water flooding, the plant dry weight reduced 50%-69%. At seedling stage, Luolijing had a stronger resistance capability against barnyardgrass (Echinochloa crusgalli var. mitis) than an alellopathic rice I-kung-pao, which meant that Luolijing had no allelopathic function. The Luolijing had a tolerance to 0.5% saline-alkaline solution.

China↗
PubMed1988

[Administration of acyclovir (virustatic) to cats].

Herpes felis infections belong to the feline viral rhinotracheitis complex. Acyclovir, a virustatic of the nucleoside-analogue-group, inhibits the in vitro replication of herpesvirus felis. Acyclovir (0.1% in isotonic saline solution) is well tolerated by cats when applied t.i.d. subcutaneously and has a high and long lasting plasma level. The treatment is not too expensive.

Acyclovir↗
PubMed2001

The effect of salinity on different developmental stages of an endemic annual plant, Aster laurentianus (Asteraceae).

Salinity reduces substrate water potential, thereby restricting water and nutrient uptake by plants; salinity may also cause ionic imbalance and toxicity. Because substrate salinity fluctuates through the growing season, a plant may be exposed to different salinity levels, at various stages of development, with potentially significant consequences on population dynamics. Here, we present the results of a study of the effect of substrate salinity on seed germination, seedling emergence, and growth of Aster laurentianus, an annual marsh plant, endemic to the Gulf of St. Lawrence and potentially threatened. Seed germination was reduced in low salt concentration (10 g sea salt/L) and completely inhibited by salinity levels >/=20 g sea salt/L. However, this inhibiting effect was reversible: seeds from the salt treatments germinated readily after being washed in distilled water. Though seedling emergence was diminished at low salinity levels, postemergence survival was little affected. Plant growth was reduced, but net carbon assimilation rate was not affected by high salinity levels. Increased root respiration and respiratory costs associated with salt tolerance might have contributed to lower C accumulation at higher salinity levels. All developmental processes considered are thus negatively affected by substrate salinity, with potentially significant consequences on population abundance and distribution in salt marshes. Yet, the tolerance of this species to high salinity levels after seedling emergence is remarkable. Seed germination represents a major bottleneck in the species life cycle, potentially controlling local distribution and abundance in the natural habitat.

Journal Article↗
PubMed1998

Effect of environmental complexity on salt-adaptation in Sorghum bicolor.

Individual plants of Sorghum bicolor mature different adaptive reactions to salinity. The positive correlation between the frequency of specific reactions and the tolerance level of plants with that specific reaction results from adaptive determinism (AD). The effect of complexity in environmental conditions on AD in plants adapting for the first time to salinity, A0, and in their offspring A1 was compared. Environmental complexity increases when uncontrolled factors besides salinity affect plants. The diversity of reactions of plants correlates positively with environmental complexity. AD correlates negatively to environmental complexity in A1. In contrast, environmental complexity has no effect on AD in A0. A1 are more tolerant to salinity than A0: A1 inherited adaptive information. The likelihood that A1 plants are exposed to the same uncontrolled factor as their parent is low, and so the decrease of AD in A1 due to environmental complexity suggests that: (1) the information inherited is specific to saline conditions; (2) AD results mainly from inherited pre-existing information; plants react as informatively closed systems: saline conditions trigger the expression of an adaptive, pre-existing program. For A0, conclusions are: (1) the adaptive reaction is not an expression of pre-existing information; (2) AD emerges during the adaptation process: the environment imprints adaptively the plant's development. In this case, plants react as open systems in terms of information.

Adaptation, Physiological↗
PubMed1982

Interaction between des-glycinamide9-[Arg8]vasopressin and serotonin on ethanol tolerance.

Sham and electrolytic lesions of the dorsal, median, and dorsal + median raphe nuclei were made in different groups of rats. One week later, daily oral treatment with ethanol (5 g/kg p.o. for 25 days) was started. This treatment produced tolerance to the hypothermic and motor impairing (moving belt test) effects of ethanol. On day 26, ethanol was stopped and subcutaneous injection of either 10 micrograms of des-Gly9-[Arg8]vasopressin (DGAVP) in saline or saline alone was started. The retention of tolerance to ethanol was measured at 3-day intervals for both hypothermia and motor-impairment. In sham-saline groups, disappearance of tolerance took 3 days for the hypothermic effect, and 9 days for the motor-impairment effect. Tolerance to both effects, however, was still observed after 9 days in DGAVP-treated rats with either sham or dorsal raphe lesions. Peptide treatment, on the other hand, failed to maintain tolerance in rats with median or median + dorsal raphe lesions. These results suggest that an intact mesolimbic serotonin pathway is necessary for the action of DGAVP on the retention of ethanol tolerance.

Animals↗
PubMed2005

Developing salt-tolerant crop plants: challenges and opportunities.

Soil salinity, one of the major abiotic stresses reducing agricultural productivity, affects large terrestrial areas of the world; the need to produce salt-tolerant crops is evident. Two main approaches are being used to improve salt tolerance: (i) the exploitation of natural genetic variations, either through direct selection in stressful environments or through mapping quantitative trait loci and subsequent marker-assisted selection; and (ii) the generation of transgenic plants to introduce novel genes or to alter expression levels of the existing genes to affect the degree of salt stress tolerance. Here, we discuss the challenges and opportunities provided by recently developed functional tools for the development of salt-tolerant crops.

Adaptation, Physiological↗
PubMed1984

Task-specific tolerance to d-amphetamine.

Rats were trained concurrently on sweetened-milk drinking and bar-press-responding behavior, which alternated on a daily basis. Dose-response functions for d-amphetamine were determined before and after conditions of chronic treatment. When given before chronic treatment, d-amphetamine decreased both milk consumption and reinforcement received for lever-pressing in a dose-dependent manner. Subsequently, three conditions of chronic injection were established in which one group received saline, prior to both tasks, another group received d-amphetamine prior to drinking milk and saline prior to lever-pressing and the third group received d-amphetamine prior to lever-pressing and saline before drinking milk. The rats became tolerant to d-amphetamine in the task in which the drug had been administered chronically; however, the same rats showed no tolerance in the other task in which saline had been administered chronically. Tolerance to d-amphetamine was thus shown to be behaviorally specific.

Animals↗
PubMed2006

Monitoring expression profiles of antioxidant genes to salinity, iron, oxidative, light and hyperosmotic stresses in the highly salt tolerant grey mangrove, Avicennia marina (Forsk.) Vierh. by mRNA analysis.

Plant photosynthesis results in the production of molecular oxygen. An inevitable consequence of this normal process is the production of reactive oxygen species (ROS) by the transfer of electrons to molecular oxygen. Plants are adequately protected by the presence of multiple antioxidative enzymes in different organelles of the plant such as chloroplasts, cytosol, mitochondria and peroxisomes. Under high light and CO(2) limiting conditions caused by environmental stress like salinity, these antioxidative enzymes play an important role in scavenging toxic radicals. To investigate the functions of antioxidative enzymes in a mangrove plant, we isolated three cDNAs encoding cytosolic Cu-Zn SOD (Sod1), catalase (Cat1) and ferritin (Fer1) from Avicennia marina cDNA library. Sod1, Cat1 and Fer1 cDNA encoded full-length proteins with 152, 492 and 261 amino acids respectively. We studied the expression of these antioxidant genes in response to salt, iron, hydrogen peroxide, mannitol and light stress by mRNA expression analysis. Cat1, Fer1 showed short-term induction while Sod1 transcript was found to be unaltered in response to NaCl stress. A decrease in mRNA levels was observed for Sod1, Cat1 while Fer1 mRNA levels remained unaltered with osmotic stress treatment. Sod1, Cat1 and Fer1 mRNA levels were induced by iron, light stress and by direct H(2)O(2) stress treatment, thus confirming their role in oxidative stress response.

Adaptation, Physiological↗
PubMed1986

Good tolerance to high-dose hepatic arterial infusion therapy.

A pilot study was designed to evaluate the efficacy of high-dose FUDR administered through the hepatic artery for the treatment of cancer involving the liver. Three dose schedules were used beginning with a dose of 0.5 mg FUDR/kg/day for 2 weeks followed by normal saline infusion for 2 weeks (schedule A). Elevation of serum bilirubin was the sole indication to deescalate to schedule B (0.3 mg FUDR/kg/day for two weeks followed by saline infusion for 4 weeks). Tolerance to this schedule escalated the patient to schedule C (0.5 mg FUDR/kg/day for 2 weeks followed by normal saline infusion for 4 weeks). Eighteen patients were treated, sixteen with metastatic colon cancer, one with metastatic leiomyosarcoma, and one with hepatoma. The patient with hepatoma developed progressive disease after one cycle of therapy. Of the 17 patients with metastatic cancer only 5 patients failed therapy yielding a 70% response rate. High-dose FUDR was well tolerated with only six patients requiring deescalation to schedule B. Elevation of alkaline phosphatase and glutamic oxaloacetic transaminase was universal. Two patients developed peptic ulceration. Sclerosing cholangitis was not observed. We conclude that high-dose FUDR administered through the hepatic artery is as safe as conventional dose infusion therapy but probably not more effective. The safety of high-dose FUDR infusion therapy suggests that sclerosing cholangitis is association with hepatic arterial infusion therapy is not related to the FUDR dose.

Drug Administration Schedule↗
PubMed1991

Antagonism of endotoxic glucose dyshomeostasis by protein kinase C inhibitors.

Activation of protein kinase C (PKC) by bacterial lipopolysaccharide had recently been implicated in the pathogenetic sequence of gram-negative sepsis, endotoxicosis, hyperinsulinism, and the alterations in glucoregulation that eventuate in glucose dyshomeostasis. This study used the peptide antibiotic polymyxin B (PMX-B) and H-7, an isoquinoline sulfonamide, as inhibitors of PKC activation to evaluate responses to provocative insulin and glucose tolerance tests in control vs. endotoxic rats. Fed male rats were treated with either Salmonella enteritidis endotoxin (ETX; 0.33 mg/kg iv) or saline 120 min before intravenous insulin tolerance testing (IVITT) with human insulin (1 U/kg) or intravenous glucose tolerance testing (IVGTT) with D-glucose (1.2 g/kg). H-7 in dimethyl sulfoxide at 25 mg/kg, PMX-B in saline at 0.25 mg/kg, or the respective vehicles were administered 5 min before the tolerance tests. Neither H-7 nor PMX-B had any significant acute effects on basal plasma glucose or lactate values. The decline in plasma with IVITT was augmented by ETX; however, concomitant H-7 or PMX-B attenuated the insulin hypoglycemia. The computed half-life of glucose in the IVGTT was decreased by ETX; however, concomitant H-7 or PMX-B decreased the tolerance alteration. In addition, both H-7 and PMX-B attenuated the rise in insulin induced by the IVGTT. Thus the hyperinsulinism and the glucoregulatory disturbances in endotoxicosis may be mediated by PKC activation and ameliorated by PKC inhibition.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1999

Repeated co-administration of caffeine and bromocriptine prevents tolerance to the effects of caffeine in the turning behavior animal model.

The present study examined the effects of repeated co-administrations of caffeine and bromocriptine for 9 consecutive days on contralateral turning in unilateral nigrostriatal 6-hydroxydopamine denervated rats. In agreement with previous data, our results showed that on the first administration, both caffeine and bromocriptine injected plus saline produced a significant increase in contralateral rotational behavior as compared to saline-saline injections. However, with repeated administrations, tolerance was observed to caffeine, but not to bromocriptine. The combination of different doses of bromocriptine (0.1, 0.2, 0.4 and 0.8 mg/kg) with caffeine (40 mg/kg) significantly enhanced the effects of either drug injected with saline on rotational behavior, and no tolerance was observed with repeated treatment. The continuous co-administration of both substances was necessary to maintain elevated levels of rotational behavior, since withdrawing one or the other drug led to decreased contralateral turning. These results demonstrate that when caffeine is administered repeatedly in combination with bromocriptine, tolerance to its psychostimulant effects is not observed, suggesting that caffeine could be used as an adjunctive therapeutic agent with dopamine agonists for the treatment of Parkinson's disease.

Adrenergic Agents↗
PubMed2006

Genetic Diversity of Microbial Eukaryotes in Anoxic Sediment of the Saline Meromictic Lake Namako-ike (Japan): On the Detection of Anaerobic or Anoxic-tolerant Lineages of Eukaryotes.

Available sequence data on eukaryotic small-subunit ribosomal DNA (SSU rDNA) directly retrieved from various environments have increased recently, and the diversity of microbial eukaryotes (protists) has been shown to be much greater than previously expected. However, the molecular information accumulated to date does still not thoroughly reveal ecological distribution patterns of microbial eukaryotes. In the ongoing challenge to detect anaerobic or anoxic-tolerant lineages of eukaryotes, we directly extracted DNA from the anoxic sediment of a saline meromictic lake, constructed genetic libraries of PCR-amplified SSU rDNA, and performed phylogenetic analyses with the cloned SSU rDNA sequences. Although a few sequences could not be confidently assigned to any major eukaryotic groups in the analyses and are debatable regarding their taxonomic positions, most sequences obtained have affiliations with known major lineages of eukaryotes (Cercozoa, Alveolata, Stramenopiles, and Opisthokonta). Among these sequences, some branched with lineages predominantly composed of uncultured environmental clones retrieved from other anoxic environments, while others were closely related to those of eukaryotic parasites (e.g. Phytomyxea of Cercozoa, Gregarinea of Alveolata, and Ichthyosporea of Opisthokonta).

Anaerobiosis↗
PubMed2002

Context-specific tolerance to the ataxic effects of alcohol.

Tolerance to alcohol and many other drugs can become conditioned to specific contextual cues present at the time of drug administration. Context-specific tolerance occurs to a variety of alcohol's effects, including changes in hormone levels, body temperature and locomotor activity. The present study investigated whether context-specific tolerance can occur to the ataxic effects of alcohol. Baseline levels of motor coordination were assessed using a tilting plane apparatus. During a 7-day tolerance acquisition phase, subjects received an injection of either alcohol (1.5 g/kg i.p.) or saline (15 ml/kg i.p.) in a novel testing room and were then placed in the tilting plane apparatus for a period of 20 min. Approximately 5 h after the first injection, subjects received a second injection in the colony room and were then placed in their home cages. One group of subjects, the paired group, received alcohol in the testing room and saline in the colony room. An unpaired group received saline in the testing room and alcohol in the colony room. A no alcohol control group received saline in both environments. Following the tolerance acquisition phase, all subjects were injected with alcohol (1.5 g/kg i.p.) and tested for ataxia in the tilting plane apparatus. Subjects in the paired group were less ataxic than subjects in the control group during all four testing blocks following alcohol administration. In contrast, subjects in the unpaired group were less ataxic than the control subjects only during the 15-min testing block. Relative to baseline scores, the paired group exhibited deficits only during the 5- and 10-min testing blocks, while subjects in the unpaired and control groups exhibited deficits during all four testing blocks. These data strongly suggest that tolerance to the ataxic effects of alcohol can become conditioned to contextual cues present at the time of alcohol administration.

Animals↗
PubMed1999

Effects of adrenaline or endotoxin tolerance states on mesenteric blood flow in endotoxaemia.

BACKGROUND: Endotoxic shock is associated with release of catecholamines as well as decreased mesenteric vascular perfusion, which is thought to cause remote organ injury. Adrenaline tolerance was reported to decrease mortality in endotoxic shock and have cross-tolerance with endotoxin tolerance. Our aim was to investigate the effect of these two tolerance conditions on the lipopolysaccharide (LPS)-induced decrease in mesenteric blood flow (MBF). METHODS: Adrenaline tolerance was developed by injecting 0.03 mg/kg adrenaline to Swiss-albino mice, gradually increasing the dose to 2 mg/kg over 5 days. Endotoxin tolerance was developed by injecting saline for 4 days and LPS 1 mg/kg at the fifth day. Control animals were injected with saline for 5 days. At 72 h after completion of injections, half of the animals in each group were challenged with saline and the other half with 20 mg/kg LPS, at 0 h. Mesenteric blood flow was measured at 4 and 24 h. RESULTS: Neither endotoxin nor adrenaline tolerance prevented an LPS-induced decrease in MBF. CONCLUSION: A low dose of LPS prior to a higher dose does not prevent an LPS-induced decrease in MBF and may actually prime for a decrease. Also, catecholamines are not primary mediators of LPS-induced decreases in MBF.

Animals↗
PubMed2006

Evidence that differential gene expression between the halophyte, Thellungiella halophila, and Arabidopsis thaliana is responsible for higher levels of the compatible osmolyte proline and tight control of Na+ uptake in T. halophila.

Salt-sensitive glycophytes and salt-tolerant halophytes employ common mechanisms to cope with salinity, and it is hypothesized that differences in salt tolerance arise because of changes in the regulation of a basic set of salt tolerance genes. We explored the expression of genes involved in two key salt tolerance mechanisms in Arabidopsis thaliana and the halophytic A. thaliana relative model system (ARMS), Thellungiella halophila. Salt overly sensitive 1 (SOS1) is a plasma membrane Na+/H+ antiporter that retrieves and loads Na+ ions from and into the xylem. Shoot SOS1 transcript was more strongly induced by salt in T. halophila while root SOS1 was constitutively higher in unstressed T. halophila. This is consistent with a lower salt-induced rise in T. halophila xylem sap Na+ concentration than in A. thaliana. Thellungiella halophila contained higher unstressed levels of the compatible osmolyte proline than A. thaliana, while under salt stress, T. halophila accumulated more proline mainly in shoots. Expression of the A. thaliana ortholog of proline dehydrogenase (PDH), involved in proline catabolism, was undetectable in T. halophila shoots. The PDH enzyme activity was lower and T. halophila seedlings were hypersensitive to exogenous proline, indicating repression of proline catabolism in T. halophila. Our results suggest that differential gene expression between glycophytes and halophytes contributes to the salt tolerance of halophytes.

Anthocyanins↗
PubMed2005

Angiotensin II-induced hypertension in mice caused an increase in insulin secretion.

OBJECTIVE AND DESIGN: Insulin action was determined in a mouse model of human hypertension via chronic angiotensin II administration followed by a glucose tolerance test. METHODS: Angiotensin II or saline was infused systemically into mice via osmotic pump for 2 or 4 weeks. In angiotensin II-treated mice versus saline controls we compared blood pressure, blood glucose, and serum insulin concentrations during an intravenous glucose tolerance test and assessed glucose transport and insulin signaling in muscle. RESULTS: Blood pressure increased at 2 and 4 weeks following angiotensin II treatment. Mice treated with angiotensin II for 4 weeks cleared a glucose bolus faster than mice treated with saline despite similar basal serum insulin concentrations. Upon glucose administration, the increase in serum insulin was greater in angiotensin II-treated mice, 38.8+/-6.5 pmol/l, compared to saline-treated mice, 21.8+/-2.9 pmol/l, but only at 4 weeks of angiotensin II treatment while no difference was observed at 2 weeks of angiotensin II administration. At 4 weeks of angiotensin II treatment, insulin signaling in the liver and in the skeletal muscle was not affected, since both the number of insulin receptors and phosphorylation of Akt were unchanged. Also at 4 weeks of angiotensin II treatment, ex vivo soleus muscle did not exhibit any change in basal and insulin-stimulated glucose uptake. CONCLUSIONS: This study suggests that long-term angiotensin II treatment for 4 weeks enhances glucose-stimulated insulin secretion in mice. Angiotensin II-induced hyperinsulinemia may play a role in the development of insulin resistance in patients with hypertension.

Angiotensin II↗