Home  About us  Contact
 

Of Effects (of + effects)

Distribution by Scientific Domains
Medical Sciences62%
Chemistry25%

Kinds of Of Effects

  • variety of effects
    		•

    Selected Abstracts

    Are CB1 receptor antagonists nootropic or cognitive impairing agents?

    DRUG DEVELOPMENT RESEARCH, Issue 8 2009
    Stephen A. Varvel
    Abstract For more than a decade, a considerable amount of research has examined the effects of rimonabant (SR 141716) and other CB1 receptor antagonists in both in vivo and in vitro models of learning and memory. In addition to its utility in determining whether the effects of drugs are mediated though a CB1 receptor mechanism of action, these antagonists are useful in providing insight into the physiological function of the endogenous cannabinoid system. Several groups have reported that CB1 receptor antagonists enhance memory duration in a variety of spatial and operant paradigms, but not in all paradigms. Conversely, disruption of CB1 receptor signaling also impairs extinction learning in which the animal actively suppresses a learned response when reinforcement has been withheld. These extinction deficits occur in aversively motivated tasks, such as in fear conditioning or escape behavior in the Morris water maze task, but not in appetitively motivated tasks. Similarly, in electrophysiological models, CB1 receptor antagonists elicit a variety of effects, including enhancement of long-term potentiation (LTP), while disrupting long-term depression (LTD) and interfering with transient forms of plasticity, including depolarization-induced suppression of inhibition (DSI) and depolarization-induced suppression of excitation (DSE). The collective results of the in vivo and in vitro studies employing CB1 receptor antagonists, demonstrate that these receptors play integral roles in different components of cognitive processing. Functionally, pharmacological blockade of CB1 receptors may strengthen memory duration, but interferes with extinction of learned behaviors that are associated with traumatic or aversive memories. Drug Dev Res 70:555,565, 2009. © 2009 Wiley-Liss, Inc. [source]

    Gabapentin Increases Slow-wave Sleep in Normal Adults

    EPILEPSIA, Issue 12 2002
    Nancy Foldvary-Schaefer
    Summary: ,Purpose: The older antiepileptic drugs (AEDs) have a variety of effects on sleep, including marked reduction in rapid-eye-movement (REM) sleep, slow-wave sleep (SWS), and sleep latency, and an increase in light sleep. The effects of the newer AEDs on sleep are unknown. Our purpose was to study the effect of gabapentin (GBP) on sleep. Methods: Ten healthy adults and nine controls were the subjects of this study. All underwent baseline and follow-up polysomnography (PSG) and completed sleep questionnaires. After baseline, the treated group received GBP titrated to 1,800 mg daily. Polygraphic variables and Epworth Sleepiness Scale (ESS) scores, a subjective measure of sleep propensity, were compared by using the Wilcoxon signed rank test. Results: Nine of the treated subjects achieved the target dose; one was studied with 1,500 mg daily because of dizziness experienced at the higher dose. GBP-treated subjects had an increase in SWS compared with baseline. No difference in the ESS or other polygraphic variables was observed. However, a minor reduction in arousals, awakenings, and stage shifts was observed in treated subjects. Conclusions: GBP appears to be less disruptive to sleep than are some of the older AEDs. These findings may underlie the drug's therapeutic effect in the treatment of disorders associated with sleep disruption. [source]

    Deep brain stimulation mechanisms: beyond the concept of local functional inhibition

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2010
    Jean-Michel Deniau
    Abstract Deep brain electrical stimulation has become a recognized therapy in the treatment of a variety of motor disorders and has potentially promising applications in a wide range of neurological diseases including neuropsychiatry. Behavioural observation that electrical high-frequency stimulation of a given brain area induces an effect similar to a lesion suggested a mechanism of functional inhibition. In vitro and in vivo experiments as well as per operative recordings in patients have revealed a variety of effects involving local changes of neuronal excitability as well as widespread effects throughout the connected network resulting from activation of axons, including antidromic activation. Here we review current data regarding the local and network activity changes induced by high-frequency stimulation of the subthalamic nucleus and discuss this in the context of motor restoration in Parkinson's disease. Stressing the important functional consequences of axonal activation in deep brain stimulation mechanisms, we highlight the importance of developing anatomical knowledge concerning the fibre connections of the putative therapeutic targets. [source]

    Differential Expression of Vasoactive Intestinal Polypeptide Receptor 1 and 2 mRNA in Murine Intestinal T Lymphocyte Subtypes

    JOURNAL OF NEUROENDOCRINOLOGY, Issue 9 2001
    B.-F. Qian
    Abstract Neuropeptides may exert a variety of effects on the immune cells at both systemic and mucosal immune sites. The immunoregulatory properties refer to the ability of physiological signals and pathways to influence various immune functions. Vasoactive intestinal polypeptide (VIP), a neuropeptide present in high concentration in gut, was studied for its production and receptor expression in intraepithelial and lamina propria T lymphocytes of mouse intestine. Using reverse transcription-polymerase chain reaction (RT-PCR) analysis, it was demonstrated that VIP receptor 1 (VIPR1) was constantly expressed in intraepithelial and lamina propria T lymphocytes from both small and large intestine. In contrast, VIPR2 was identified only in T cells from small intestine. Further studies on purified subpopulations of T lymphocytes indicated the existence of VIPR2 in CD8+ T cells, but not CD4+ and CD4CD8 double negative T cells, although all these three subpopulations displayed VIPR1. In addition, VIPR1 mRNA was detected in splenic T lymphocytes, but no signal was obtained for VIPR2 mRNA, even after stimulation of the cells with anti-CD3,-chain mAb, phorbol 12-myristate 13-acetate (PMA) and/or VIP. The presence of VIP receptor(s) on intestinal T lymphocytes was supported by the detection of VIP on the cell surface using dual colour immunoflowcytometry. In-vitro treatment with VIP resulted in a tendency towards an increased size of the VIP immunoreactive T cell population and significantly enhanced the average immunofluorescence intensity of the surface labelling. This indicates that the receptors are partially occupied by locally produced VIP in vivo and that more peptide molecules can be bound on the lymphocytes when needed, released and accumulated in higher concentration at the action sites. We failed to detect the expression of VIP mRNA in T lymphocytes, from either intestine or spleen. These observations support that VIP may be an important immune modulator in gut acting through specific receptors on T lymphocytes. The differential mRNA expression of VIP receptor subtypes in cells with different phenotypes and in different immune compartments may suggest diverse regulatory roles of the neuropeptide in immune responses. [source]

    Chronic Intermittent Injections of High-Dose Ethanol During Adolescence Produce Metabolic, Hypnotic, and Cognitive Tolerance in Rats

    ALCOHOLISM, Issue 10 2003
    Janelle M. Silvers
    Background: Many humans are first exposed to ethanol during adolescence, the time at which they are most likely to binge drink ethanol. Chronic intermittent ethanol (CIE) exposure produces ethanol tolerance in adolescent rodents. Recent studies suggested that adolescent animals administered CIE experienced increased cognitive impairment following an ethanol challenge. These studies further explore development of ethanol tolerance caused by CIE in adolescence, and whether CIE during adolescence leads to altered ethanol response in adulthood. Methods: Beginning postnatal day (P) 30, adolescent rats were administered 5.0 g/kg ethanol or saline every 48 hours for 20 days. In experiment I, animals were tested for differential weight gain. In experiment II, loss of righting reflex (LORR) was observed after each injection, then at completion of pretreatment all animals were tested with 5.0 g/kg ethanol and LORR was observed. In experiment III, blood ethanol levels were observed and elimination rates calculated after the first and fifth pretreatments. All animals were tested with 5.0 g/kg at completion of pretreatment and elimination rates were recalculated. In experiment IV, animals were trained on the spatial version of the Morris Water Maze Task (MWMT) on non-treatment days. Following completion of pretreatment and training, animals were tested after receiving an ethanol (1.0, 1.5, or 2.0 g/kg), or saline. Tests for experiments II, III, and IV were repeated in the same animals following 12 ethanol-free days. Results: Chronic intermittent ethanol exposure during adolescence caused differential weight gain (experiment I). Adolescent rats developed tolerance to ethanol-induced LORR (experiment II) and metabolic tolerance to ethanol (experiment III). This tolerance was seen after 12 ethanol-free days. CIE also attenuated ethanol-induced spatial memory deficits in the MWMT (experiment IV). This effect was not long-lasting. Conclusions: Following CIE pretreatment during adolescence, tolerance developed to the hypnotic and cognitive impairing effects of ethanol, along with increased metabolic rate and decreased weight gain. These results further emphasize the ability of CIE to produce a variety of effects during adolescence, some having long-lasting consequences. [source]

    Insecticidal activity of the pyrimidine nucleoside analogue (E)-5-(2-bromovinyl)-2,-deoxyuridine (BVDU)

    PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 8 2005
    Dr Michael Breuer
    Abstract The insecticidal activity of the antiherpetic agent (E)-5-(2-bromovinyl)-2,-deoxyuridine (BVDU) was assessed in in vivo assays against the fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera, Noctuidae). BVDU, mixed into an artificial diet, caused a variety of effects, depending on the concentration used. Compared with controls, food intake was lower, larval growth was retarded and larval development was prolonged. The treated larvae formed smaller pupae and the hatching moths often showed morphogenetic defects. A higher mortality could be found in larval and pupal stages and was generally caused by moult disruption. A choice assay showed that BVDU has very slight feeding-deterrent properties, which only partly explain the toxic effects. The agent most probably acts through its cytostatic activity that has been described previously using cell lines of different insect species. Copyright © 2005 Society of Chemical Industry [source]

    Alteration of the disulfide-coupled folding pathway of BPTI by circular permutation

    PROTEIN SCIENCE, Issue 5 2004
    Grzegorz Bulaj
    BPTI, bovine pancreatic trypsin inhibitor; cBPTI, a circular form of BPTI generated by forming a peptide bond between the natural termini; cpBPTI, circularly permuted BPTI. Abstract The kinetics of disulfide-coupled folding and unfolding of four circularly permuted forms of bovine pancreatic trypsin inhibitor (BPTI) were studied and compared with previously published results for both wild-type BPTI and a cyclized form. Each of the permuted proteins was found to be less stable than either the wild-type or circular proteins, by 3,8 kcal/mole. These stability differences were used to estimate effective concentrations of the chain termini in the native proteins, which were 1 mM for the wild-type protein and 2.5 to 4000 M for the permuted forms. The circular permutations increased the rates of unfolding and caused a variety of effects on the kinetics of refolding. For two of the proteins, the rates of a direct disulfide-formation pathway were dramatically increased, making this process as fast or faster than the competing disulfide rearrangement mechanism that predominates in the folding of the wild-type protein. These two permutations break the covalent connectivity among the ,-strands of the native protein, and removal of these constraints appears to facilitate direct formation and reduction of nearby disulfides that are buried in the folded structure. The effects on folding kinetics and mechanism do not appear to be correlated with relative contact order, a measure of overall topological complexity. These observations are consistent with the results of other recent experimental and computational studies suggesting that circular permutation may generally influence folding mechanisms by favoring or disfavoring specific interactions that promote alternative pathways, rather than through effects on the overall topology of the native protein. [source]

    A polymorphism within IL21R confers risk for systemic lupus erythematosus

    ARTHRITIS & RHEUMATISM, Issue 8 2009
    Ryan Webb
    Objective Interleukin-21 (IL-21) is a member of the type I cytokine superfamily that has a variety of effects on the immune system, including B cell activation, plasma cell differentiation, and immunoglobulin production. The expression of IL-21 receptor (IL-21R) is reduced in the B cells of patients with systemic lupus erythematosus (SLE), while serum IL-21 levels are increased both in lupus patients and in some murine lupus models. We recently reported that polymorphisms within the IL21 gene are associated with increased susceptibility to SLE. The aim of this study was to examine the genetic association between single-nucleotide polymorphisms (SNPs) within IL21R and SLE. Methods We genotyped 17 SNPs in the IL21R gene in 2 large cohorts of lupus patients (a European-derived cohort and a Hispanic cohort) and in ethnically matched healthy controls. Results We identified and confirmed the association between rs3093301 within the IL21R gene and SLE in the 2 cohorts (meta-analysis odds ratio 1.16 [95% confidence interval 1.08,1.25], P = 1.0 × 10,4). Conclusion Our findings indicate that IL21R is a novel susceptibility gene for SLE. [source]