Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “salinity tolerance”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMedDate not supplied

Decreased behavioral effects of daily intracerebroventricular bombesin.

Intracerebroventricular (ICV) bombesin increases grooming and decreases food intake in rats. We examined tolerance to these effects by administering a daily injection of either saline or 25 ng bombesin to rats for 8 days via lateral ventricular cannulas. Food intake and grooming were monitored. After 8 days bombesin no longer increased grooming or decreased food intake in bombesin-treated rats, but did increase grooming and decrease food intake in saline-treated rats. This development of behavioral tolerance conflicts with previous reports using larger doses and demonstrates that repeated small doses of ICV bombesin produce different effects from larger doses.

Animals↗
PubMed1993

Diphosphoryl lipid A from Rhodopseudomonas sphaeroides induces tolerance to endotoxic shock in the rat.

OBJECTIVES: To examine the hemodynamic effects of diphosphoryl lipid A from Rhodopseudomonas sphaeroides and to examine the ability of this substance to induce tolerance to endotoxic shock. DESIGN: Randomized, prospective, controlled study comparing the hemodynamic actions of R. sphaeroides diphosphoryl lipid A to those effects of lipopolysaccharide form Salmonella minnesota, followed by a prospective, randomized, controlled study comparing pretreatment with R. sphaeroides diphosphoryl lipid A and phosphate-buffered saline in the induction of tolerance to endotoxic shock. SETTING: Laboratory of the Section of Critical Care Medicine at a University Hospital. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Eight rats were randomized to receive intravenous R. sphaeroides diphosphoryl lipid A, 0.5 mg/100 g body weight or S. minnesota lipopolysaccharide, 0.5 mg/100 g body weight. Ten rats were then randomized to receive R. sphaeroides diphosphoryl lipid A, 0.5 mg/100 g body weight, or phosphate-buffered saline intravenously 48 hrs before receiving S. minnesota lipopolysaccharide, 5 mg/100 g body weight, by intravenous infusion. MEASUREMENTS AND MAIN RESULTS: Cardiac index was significantly decreased from baseline in rats treated with lipopolysaccharide; there was no significant change in the R. sphaeroides diphosphoryl lipid A group. Peak circulating tumor necrosis factor (TNF) concentrations in the lipopolysaccharide-treated rats were higher than in R. sphaeroides diphosphoryl lipid A-treated rats (3.1 +/- 1.0 vs. 1.5 +/- 0.4 ng/mL). R. sphaeroides diphosphoryl lipid A significantly attenuated lipopolysaccharide-induced changes in mean arterial pressure and cardiac index. At baseline, there was no significant difference in serum TNF concentrations between rats pretreated with R. sphaeroides diphosphoryl lipid A and those rats pretreated with phosphate-buffered saline. TNF levels peaked at 1 hr post-lipopolysaccharide infusion at 4.3 +/- 0.6 ng/mL in the phosphate-buffered saline group and at 2.0 +/- 0.5 ng/mL in the R. sphaeroides diphosphoryl lipid A group (p < .02). Four of five rats pretreated with R. sphaeroides diphosphoryl lipid A survived endotoxic shock, whereas none of the phosphate-buffered saline-pretreated rats survived (p = .05). CONCLUSIONS: These observations are consistent with previous reports of the limited toxic effects of R. sphaeroides diphosphoryl lipid A and suggest that this molecule retains the ability to induce tolerance to endotoxic shock.

Animals↗
PubMed1999

Loss of tolerance to amphetamine-induced hypophagia in rats: homeostatic readjustment vs. instrumental learning.

According to the homeostatic model, the loss of tolerance to amphetamine-induced hypophagia requires a period of unrestricted feeding in the drug-free state, which transforms the compensatory response mediating tolerance ("hyperhunger") into a functional disturbance to homeostasis. In the absence of such a disturbance, tolerance should be retained. To test this prediction, rats tolerant to amphetamine's hypophagic effect were given a 4-week tolerance retention period during which milk intakes were restricted and deprivation levels held relatively constant. During this period the rats were assigned to one of the following drug treatment conditions: 1) saline injections both before and after daily milk tests (saline group); 2) saline injections before, and amphetamine injections after, daily milk tests (after group); 3) no injections and no milk tests (no-treatment group); or 4) amphetamine injections before, and saline injections after, milk tests (before group). Despite the restricted feeding regimen, both the saline and after groups lost tolerance. These results do not support the homeostatic model, but are consistent with the instrumental learning model, which views drinking milk in the undrugged state as analogous to receiving noncontingent reinforcement.

Animals↗
PubMed1988

Spinal infusion of opiate and alpha-2 agonists in rats: tolerance and cross-tolerance studies.

Intrathecal morphine or ST-91, an alpha-2 agonist, produce potent antinociception in a number of animal models. Using osmotic minipumps and a new Y-catheter technique, we show that chronic intrathecal (i.t.) infusion of morphine (2, 6 or 20 nmol/microliter/hr) or ST-91 (3, 10 or 30 nmol/microliter/hr) in rats produces a dose-dependent increase in hot-plate latency 1 day after pump implant. By 4 to 5 days after initiation of chronic infusion of either drug, hot-plate latencies do not differ from saline-infused controls. Rats rendered tolerant to one of the three chronic i.t. morphine doses (2, 6 or 20 nmol/microliter/hr) and tested at 7 days after initiation of infusion with a bolus i.t. dose of morphine, show a dose-dependent rightward shift in hot-plate dose-response curves. The two lower doses of chronic i.t. infusions of morphine produce parallel shifts of the subsequent i.t. administered morphine dose-response curves, but the highest chronic i.t. dose of morphine (20 nmol/microliter/hr) produces a significantly greater slope of the subsequent i.t. administered morphine dose-response curve. Animals exposed to chronic i.t. infusion of one of three doses of ST-91 (3, 10 or 30 nmol/microliter/hr) display a parallel, dose-dependent rightward shift to a subsequent bolus i.t. injection of ST-91. Rats rendered tolerant to chronic i.t. infusions of ST-91 showed no difference in the response to i.t. administered morphine hot-plate dose-response curves as compared to saline infused controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1992

Effects of chronic treatment with ethanol on the development of cross-tolerance to other alcohols and pentobarbital.

The development of cross-tolerance to various alcohols and pentobarbital was examined in ethanol (EtOH)-treated mice. Chronic EtOH treatment (dosage rising in steps from 3.5-4.5 g/kg i.p. daily during a 23-day period) produced tolerance to its hypnotic effect. Such tolerance was seen as a reduction in the duration of loss of righting reflex (LRR), as well as higher blood EtOH levels at the offset of LRR, in EtOH-treated mice as compared to saline-treated controls. Cross-tolerance was shown by shifts in dose-response curves for the LRR induced by n-propanol and t-butanol. Such treatment, however, did not confer functional cross-tolerance to n-butanol and pentobarbital. Because n-butanol and pentobarbital are more lipid-soluble, whereas EtOH, n-propanol and t-butanol have low degrees of lipid solubility, the development of cross-tolerance among these sedative-hypnotic drugs might be related to their relative degrees of lipid solubility.

1-Butanol↗
PubMed2001

Relationship between allozyme genotype and sensitivity to stressors in the western mosquitofish Gambusia affinis detected for elevated temperature but not mercury.

Previous studies with Gambusia holbrooki have found associations of allozyme genotype with tolerance to metals, pesticides, heat, and salinity. To examine the generality of these relationships, we looked for similar associations of mercury and heat tolerance with allozyme genotype at the GPI-2, MDH-1 and MDH-2 loci in its sister species Gambusia affinis. This was done to assess if the loci themselves or closely linked loci were associated with mercury tolerance, because weaker linkage associations would be unlikely to persist across species boundaries. Moreover, the use of two very different types of stress allowed us to determine if the higher tolerance of particular allozyme genotypes is specific to a certain stress or reflects a higher tolerance to stress in general. Associations between genotype and tolerance to mercury and heat were determined in laboratory exposures of about 875 fish in each of two exposures where tolerance was measured as time-to-death, followed by electrophoresis on cellulose acetate gels. For none of the three loci did we find an association of genotype with tolerance to mercury. This contrasts with reports of such an association for GPI-2 and MDH-1 in G. holbrooki, so our results do not support the hypothesis that observed associations between allozyme genotypes and mercury tolerance are due to the allozymes or closely linked loci. However, our comparison was weakened by a scarcity of the GPI-2 genotypes reported to be mercury sensitive in G. holbrooki. Furthermore, rapid mortality in our mercury exposure may have affected the ability to detect genotypic differences in survival. The MDH-1 heterozygote showed higher tolerance to heat stress compared to homozygotes, although this difference was only significant for the most common homozygous genotype. No such relationship between MDH-1 and heat stress has been reported in G. holbrooki. We found no evidence that associations between allozyme genotype and tolerance are similar for different types of stresses, which could be an advantage for using allozymes as an indicator of exposure history to a stressor. Our study also showed that G. affinis sex and weight influence tolerance to mercury and heat.

Aldose-Ketose Isomerases↗
PubMed1980

Enhanced phagocytosis and bactericidal activity of hepatic reticuloendothelial system during endotoxin tolerance.

The effects of tolerance to Escherichia coli endotoxin on the phagocytic and bactericidal activity of the hepatic reticuloendothelial system against viable E. coli were examined using ex vivo perfused rat livers. Livers were isolated from control and endotoxin-tolerant rats and perfused with a medium containing 5% homologous serum from either control or tolerant rats. After the addition of the E. coli (2 x 10(7) cells per ml) to the perfusate, the hepatic clearance of the bacteria was followed for 30 min. The highest activation of the hepatic reticuloendothelial system was observed when serum from tolerant animals was added to the perfusate. Under these conditions phagocytosis was 47% (12% in controls), and 37 to 38% of the bacteria were killed (5% in controls). This activation was less when livers obtained from tolerant rats were perfused with serum from controls or with saline only. The data suggests that, during endotoxin tolerance, humoral factors play an important role in the activation of the hepatic reticulendothelial system, although a direct stimulation of Kupffer cells also occurs. The enhancement of phagocytosis by tolerant serum did not require the presence of homologous antibodies and involved the activation of the alternative complement pathway, since it was lost after removal of factor B activity. On the other hand, stimulation of intracellular killing required both complement and specific antibodies. The data suggest a role of endotoxin in the activation of humoral and cellular mechanisms involved in the host resistance to gram-negative bacterial infection.

Animals↗
PubMed1985

Osmotic control in marine animals.

The sea is the home of two types of animal; primary marine inhabitants of wholly marine ancestry (mainly invertebrates) and secondary marine inhabitants (mainly fish and higher vertebrates) which have had a freshwater or terrestrial phase in their evolutionary history. The former have blood osmolarities close to that of seawater, and only encounter osmotic problems at the sea's margins (e.g. intertidal zones, lagoons, estuaries) where salinities are different from the open sea; the latter have low blood concentrations and potentially have problems of salt loading and water loss in seawater. Most primary marine inhabitants are stenohaline, live in the open sea and encounter no osmotic stress, and can tolerate little change in external salinity. The bulk of their euryhaline relatives living in the more demanding environments of littoral zones and estuaries rely heavily upon behavioural osmotic control. Sessile animals employ isolation responses (burrowing, shell valve closure etc.) when external salinities are stressful; mobile species have been little studied, but some are known to avoid deleterious salinities or choose optimum concentrations. The existence of predictive and reactive categories of behavioural osmotic control in mobile animals is suggested. Intracellular osmotic regulation by changes in the size of the pool of non-essential amino acids is the basis of much penetration of brackish/hypersaline water by primary marine inhabitants; however, it is doubtful whether changes in amino acid concentration are rapid enough to prevent cellular swelling/shrinkage in animals exposed to short-term salinity fluctuations (e.g. in estuaries, splash-zone pools). Extracellular osmoregulation is characteristic of fish, many euryhaline crustacea and a few representatives of other groups. It depends primarily on salt pumps (located usually at gut and/or gill) but low integumentary permeabilities to salt and water are equally essential. The permeability of teleost eggs to salt and water is given special consideration because of their hypo-osmotic state and apparent absence of osmoregulatory structures. In elasmobranchs and coelocanths the problems of salt loading and water loss have effectively been met by separate mechanisms. Osmotic water loss is opposed by high blood concentrations of urea (maintained by renal reabsorption and low branchial permeability) which result in a total blood osmolarity rather higher than that of the external medium.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗
PubMed2002

[Research progress in salt tolerance genes of SOS in Arabidopsis thaliana].

The soil salination is a significant abiotic stress for agricultural production and ecological environment. The research on salt tolerance represents an important part for basic plant biology. Genetic analysis of salt tolerance genes in Arabidopsis has become a central issue in this research areas. In recent years, efforts from some laboratories in the world have led to some significant progresses in this field. In this paper, we will review the progress in salt tolerance genes SOS (salt overly sensitive): SOS1,SOS2 and SOS3.

English Abstract↗
PubMed2004

Cloning and functional analysis of a novel DREB1/CBF transcription factor involved in cold-responsive gene expression in Zea mays L.

The transcription factors DREB1s/CBFs specifically interact with the DRE/CRT cis-acting element (core motif: G/ACCGAC) and control the expression of many stress-inducible genes in Arabidopsis. We isolated a cDNA for a DREB1/CBF homolog, ZmDREB1A in maize using a yeast one-hybrid system. The ZmDREB1A proteins specifically bound to DRE and the highly conserved valine at the 14th residue in the ERF/AP2 DNA binding domain was a key to determining the specific interaction between this protein and the DRE sequence. Expression of ZmDREB1A was induced by cold stress and slightly increased by high-salinity stress. This gene was also transiently expressed by mechanical attack. ZmDREB1A activated the transcription of the GUS reporter gene driven by DRE in rice protoplasts. Overexpression of ZmDREB1A in transgenic Arabidopsis induced overexpression of target stress-inducible genes of Arabidopsis DREB1A resulting in plants with higher tolerance to drought and freezing stresses. This indicated that ZmDREB1A has functional similarity to DREB1s/CBFs in Arabidopsis. The structure of the ERF/AP2 domain of ZmDREB1A in maize is closely related to DREB1-type ERF/AP2 domains in the monocots as compared with that in the dicots. ZmDREB1A is suggested to be potentially useful for producing transgenic plants that is tolerant to drought, high-salinity and/or cold stresses.

Amino Acid Sequence↗
PubMed1975

Negative reinforcing properties of some psychotropic drugs in drug-naive rhesus monkeys.

Rhesus monkeys, previously trained to avoid electric shock, pressed a lever to extinguish a light associated with an intravenous drug infusion scheduled to occur 30 seconds after the onset of the light. Each response when the light was on terminated the light for a 1-minute time-out period (avoidance); a response during the infusion terminated the infusion (escape). Under these conditions the monkeys tolerated a high number of saline infusions. Saline was replaced by different doses of chlorpromazine, lysergic acid diethylamide (LSD) and pentobarbital each for six successive daily 2-hour sessions. Infusions of chlorpromazine (5.0-20 mug/kg/infusion) or LSD (1.0-2.5 mug/kg/infusion) generated and maintained avoidance/escape behavior, whereas most of the infusions of pentobarbital (10-100 mu/kg/infusion) were tolerated. In rhesus monkeys with no previous drug experience, chlorpromazine and LSD, but not pentobartital, have negative reinforcing properties.

Animals↗
PubMed1993

Effect of anisomycin on the development of rapid tolerance to ethanol-induced motor impairment.

Male Wistar rats given a single moderate dose (1.7 g/kg, IP) of ethanol (EtOH), followed by six trials on the moving belt apparatus during the next hour, showed functional tolerance to the motor-impairing effects of a second dose given 24 h later if the first EtOH was preceded and followed by an injection of saline. The same EtOH dose and intoxicated practice did not produce tolerance if the saline injections were replaced by two doses of anisomycin (60 mg/kg each, SC) 15 min before and 105 min after the first dose of EtOH. This finding suggests that rapid tolerance, like chronic tolerance, requires de novo synthesis of protein during a short period immediately related to the test experience.

Animals↗
PubMed2026

MdWRKY75 interacts with MdWOX11 to modulate root growth under salt stress in apple.

The root system is pivotal for plant development, enabling both vegetative growth and tolerance to abiotic stresses like salinity. However, the molecular mechanisms governing root adaptive development in response to salt stress remain poorly understood in apple (Malus domestica Borkh.). In this study, we identified the salt stress-responsive WRKY transcription factor MdWRKY75. Overexpression of MdWRKY75 in transgenic apple negatively regulates adventitious root (AR) formation and salt stress tolerance, whereas reducing MdWRKY75 expression yields the opposite phenotype. Moreover, MdWRKY75 directly binds to the promoter of MdSAUR15 (SMALL AUXIN UP RNA15) and transcriptionally represses the expression of MdSAUR15, which, when overexpressed, promotes AR formation and enhances salt stress tolerance. We further demonstrated that MdWRKY75 interacts with MdWOX11, a WUSCHEL-related homeobox (WOX) transcription factor, both in vitro and in vivo. MdWOX11 expression is upregulated and enhances AR formation under salt stress. Additionally, MdWOX11 reduces the binding of MdWRKY75 to the MdSAUR15 promoter, and alleviates the MdWRKY75-mediated inhibitory effect on MdSAUR15 expression. Collectively, our study provides a MdWOX11-MdWRKY75-MdSAUR15 module regulating root adaptation in response to salt stress in apple.

Malus↗
PubMed1980

Influence of small increments of epinephrine on glucose tolerance in normal humans.

To ascertain whether small elevations of epinephrine alter glucose tolerance, we infused epinephrine or saline into seven healthy volunteers for 5 hours. Two hours after starting the infusions, subjects ingested 100 g of glucose. Plasma epinephrine (basal 23 +/- 4 pg/mL) rose during epinephrine infusion to levels (75 to 80 pg/mL) similar to those observed in nine outpatients presenting with mild viral illnesses (66 +/- 8 pg/mL). Although epinephrine produced only a small (5 mg/dL) increase n plasma glucose before glucose ingestion, after oral glucose the levels of glucose increased by 30 to 60 mg/dL above saline control values (163 +/- 14 mg/dL versus 108 +/- 15 at 2 h, p < 0.005). This diabetogenic effect occurred despite two-fold higher insulin levels and normal suppression of plasma glucagon. We conclude that small physiologic increments of epinephrine, which cause minimal changes in fasting plasma glucose, produce a marked reduction in glucose tolerance. Our data suggest marked sensitivity to the insulin antagonistic effects of epinephrine and may provide a mechanism for stress-induced glucose intolerance.

Adolescent↗
PubMed1994

The NMDA receptor antagonists, LY274614 and MK-801, and the nitric oxide synthase inhibitor, NG-nitro-L-arginine, attenuate analgesic tolerance to the mu-opioid morphine but not to kappa opioids.

Once daily s.c. administration of 5 mg/kg morphine, a mu-opioid agonist, or U50488H (U50), a kappa 1-opioid agonist, for 5 days in male CD-1 mice results in a 2-3-fold shift to the right of the respective analgesic (tail flick) dose-response curves, indicating the development of tolerance. Concurrent s.c. administration of the competitive NMDA receptor antagonist, LY274614 (LY), at 24 mg/kg/24 h infusion (osmotic pump) or 6 mg/kg i.p. once daily attenuates the development of morphine tolerance, when the response to saline plus morphine is compared on day 5 with LY plus morphine. Using this paradigm, once daily administration of either the non-competitive NMDA antagonist, MK-801, at 0.3 mg/kg i.p. or the nitric oxide synthase inhibitor, NG-nitro-L-arginine (NorArg), at 1 mg/kg i.p. twice daily attenuated the development of morphine tolerance. None of these drugs modify the tail-flick response or alter the ED50 for morphine. In contrast, co-administration of LY, MK-801 or NorArg, as above, failed to attenuate the development of tolerance to U50 or to the kappa 3-opioid agonist, naloxone benzoylhydrazone (NalBzoH). These results suggest that mu-opioid tolerance but not kappa 1- or kappa 3-opioid tolerance involves the mediation of NMDA receptors and the nitric oxide system.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1996

Pancreatic A-cell function in the partially pancreatectomized Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous non-insulin-dependent diabetes mellitus.

We examined whether a 70% pancreatectomy changes the morphofunctionality of pancreatic A cells in a model rat (Otsuka Long-Evans Tokushima Fatty [OLETF]) with non-insulin-dependent diabetes mellitus. Male OLETF rats aged 6 weeks were assigned to two groups: partial pancreatectomy (Px) and sham pancreatectomy (sham). The Px group was divided into three subgroups based on treatment received after surgery, which included treatment with nicotinamide, phlorhizin, or saline. As a control, their diabetes-resistant counterparts, Long-Evans Tokushima Otsuka (LETO) rats, were similarly treated and grouped. Six weeks after surgery, plasma glucagon responses to arginine- and insulin-induced hypoglycemia were examined. In addition, the glucagon content and morphological features of pancreatic A cells in Px-remnant and remnant-equivalent pancreata were investigated 7 weeks after surgery. A sustained nonfasting hyperglycemia was evident in Px OLETF rats, which was ameliorated by administration of nicotinamide. The glucagon content and A-cell mass were not decreased significantly in the remnant pancreas of saline- and phlorhizin-treated Px animals of either strain but increased in nicotinamide-treated animals compared with those in the remnant equivalent of the respective sham rats. The areas under the response curves of plasma glucagon (zigma IRG) during an arginine infusion test and 90 minutes of insulin-induced hypoglycemia were 1,010.7 +/- 72.9, 1,083.1 +/- 95.3, 1,029.6 +/- 65.0, and 1,779.8 +/- 226.9 pmol.L-1.min-1 versus 1,997.0 +/- 283.1,2,217.0 +/- 395.0, 1,479.6 +/- 78.0, and 3,466.4 +/- 174.0 pmol.L-1.min-1 in phlorhizin-, nicotinamide-, and saline-treated Px OLETF and sham OLETF rats, respectively. A similar trend was observed for differences in the response of pancreatic A cells to both stimuli among various groups of LETO rats. There was no significant difference in sigma IRGs during both tests between OLETF and LETO rats with similar treatments, except during an insulin tolerance test (ITT) in saline-treated Px rats. The magnitude of the plasma glucagon response to both stimuli in the test animals was roughly parallel to the glucagon content in the pancreas. These findings suggest that differences in the proliferation and responsiveness of pancreatic A cells between OLETF and LETO rats after a 70% pancreatectomy are not nearly as significant as compared with B cells.

Animals↗
PubMed1977

Reinforcing properties of perphenazine, haloperidol and amitryptiline in rhesus monkeys.

Possible negative reinforcing effects of perphenazine, haloperidol and amitryptiline were studied in rhesus monkeys previously trained to avoid electric shock by responding. Responding extinguished a light associated with an intravenous drug infusion scheduled to occur 30 seconds after the light was switched on. A response occurring when the light was on switched the light off for a period of 1 minute (time-out period). a response during the infusion terminated the infusion. Under these conditions, the monkeys tolerated a large number of saline infusions. Saline was replaced by different doses of perphenazine, haloperidol and amitryptiline, each for 12 successive daily 2-hour sessions. Infusions of perphenazine (0.50-1.6 microng/kg) and to a lesser extent infusions of haloperidol (2.5 microng/kg) generated and maintained responding. Most of the infusions of amitryptiline in the dose range of 1.0 to 10.0 microng/kg were tolerated. Haloperidol and perphenazine in doses higher than 10.0 micmitryptiline (500-3000 microng/kg i.v.) had no influence on shock avoidance behavior. Positive reinforcing effects of these compounds were studied in a group of monkeys trained to respond under a 10 response fixed ratio of intravenous infusions of codeine. None of the three compounds maintained responding previously engendered by codeine.

Amitriptyline↗