Biomedical subjects

E Dere

Publications and source records attributed to E Dere.

5 recordsLinked to original sources

PubMed2003

NMDA-receptor antagonism via dextromethorphan and ifenprodil modulates graded anxiety test performance of C57BL/6 mice.

The majority of N-methyl-D-aspartate receptors (NMDA-R) in the adult forebrain are di- or triheteromers composed of NR1, NR2A and NR2B subunits. Subunit non-selective NMDA-R antagonists produce anxiolytic-like effects together with motor and sensory side-effects. The graded anxiety test (GAT), permits the within-task distinction of drug effects on anxiety from those on activity and perception. By testing NMDA-R subunit selective agents in the GAT it might be possible to determine whether their effects on anxiety, activity and perception are interrelated, and whether separate NMDA-R subtypes are involved. Dextromethorphan (weakly NR2A-selective) (10 and 30 mg/kg, i.p.) and ifenprodil (highly NR2B-selective) (1, 3 and 5 mg/kg, i.p.) were tested in the GAT. Both drugs failed to induce anxiolysis devoid of side-effects. However, the 10 mg/kg dose of dextromethorpan showed an anxiolytic, whereas the 30 mg/kg dose showed an anxiogenic, behavioral profile. Since the selective blockade of the NR2B subunit by ifenprodil had no clear anxiolytic effect, the anxiolytic potential of NMDA subunit non-selective agents might involve NR2A-containing receptors.

Animals↗

PubMed2002

GP3: GenePix post-processing program for automated analysis of raw microarray data.

UNLABELLED: Here we describe an automated and customizable program to correct, filter and normalize raw microarray data captured using GenePix, a commonly used microarray image analysis application. Files can be processed individually or in batch mode for increased throughput. User defined inputs specify the stringency of data filtering and the method and conditions of normalization. The output includes gene summaries for replicate spots and descriptive statistics for each experiment. The source code (Perl) can also be adapted to handle raw data output from other image analysis applications. AVAILABILITY: http://bch.msu.edu/~zacharet/microarray/GP3.html

Algorithms↗

PubMed2001

Unaltered radial maze performance and brain acetylcholine of the endothelial nitric oxide synthase knockout mouse.

Proceeding from previous findings of a beneficial effect of endothelial nitric oxide synthase (eNOS) gene inactivation on negatively reinforced water maze performance, we asked whether this improvement in place learning capacities also holds for a positively reinforced radial maze task. Unlike its beneficial effects on the water maze task, eNOS gene inactivation did not facilitate radial maze performance. The acquisition performance over the days of place learning did not differ between eNOS knockout (eNOS-/-) and wild-type mice (eNOS+/+). eNOS-/- mice displayed a slight and eNOS+/+ mice a more severe working memory deficit in the place learning version of the radial maze compared to the genetic background C57BL/6 strain. Possible differential effects of eNOS inactivation, related to differences in reinforcement contingencies between the Morris water maze and radial maze tasks, behavioral strategy requirements, or to different emotional and physiological concomitants inherent in the two tasks are discussed. These task-unique characteristics might be differentially affected by the reported anxiogenic and hypertensional effects of eNOS gene inactivation. Post-mortem determination of acetylcholine concentrations in diverse brain structures revealed that acetylcholine and choline contents were not different between eNOS-/- and eNOS+/+ mice, but were increased in eNOS+/+ mice compared to C57BL/6 mice in the frontal cortex. Our findings demonstrate that phenotyping of learning and memory capacities should not rely on one learning task only, but should include tasks employing both negative and positive reinforcement contingencies in order to allow valid statements regarding differences in learning capacities between rodent strains.

Acetylcholine↗

PubMed2000

Superior water maze performance and increase in fear-related behavior in the endothelial nitric oxide synthase-deficient mouse together with monoamine changes in cerebellum and ventral striatum.

Nitric oxide (NO) has been implicated in the control of emotion, learning, and memory. We have examined endothelial NO synthase-deficient mice (eNOS-/-) in terms of habituation to an open field, elevated plus-maze behavior, Morris water maze performance, and changes in cerebral monoamines. In the open field, eNOS-/- animals were less active than wild-type controls but showed unimpaired habituation. In the plus-maze, an anxiogenic effect was observed. Proceeding from previous findings of deficits in hippocampal and neocortical long-term potentiation (LTP) in our eNOS-/- mice, we investigated whether these animals also express deficits in learning tasks that have been linked to hippocampal function and LTP. Unexpectedly, eNOS gene disruption led to accelerated place learning in the water maze. Furthermore, during long-term retention and reversal learning, eNOS-/- mice showed improved performance. In a cued version of the water maze task, eNOS-/- and control mice did not differ, implying that the superior performance of eNOS-/- animals on the former tasks cannot be attributed solely to differences in sensorimotor capacities. The neurochemical evaluation of the eNOS-/- mice revealed increases in the concentrations of the serotonin metabolite 5-HIAA in the cerebellum, together with an accelerated serotonin turnover in the frontal cortex. Furthermore, eNOS-/- mice had a higher dopamine turnover in the ventral striatum. These findings are discussed in terms of possible concomitant effects on physiological parameters, such as a decreased reactivity of GABAergic neurotransmission or changes in vascular functions, and effects on behavioral processes related to reinforcement, learning, and emotion.

3,4-Dihydroxyphenylacetic Acid↗

PubMedDate not supplied

Enhanced maze performance and reduced oxidative stress by combined extracts of zingiber officinale and ginkgo biloba in the aged rat.

Here we assessed the effects of i.g. administration of Zingicomb (ZC), a mixture of zingiber officinale and ginkgo biloba extracts, on learning and memory, and on indicators of oxidative stress in aged rats. Effects of ZC (1 and 10 mg/kg) were investigated in 22-24 months old Wistar rats using the Morris water maze, in which they show deficient performance as compared to 3 months old rats in the undrugged state (days 1 and 2). Treatment was administered on days 3 and 4 of training, then over 7 days with training discontinued, and again on days 5 and 6 when training was resumed. Thereafter chronic treatment was maintained over 5 months. 1 mg/kg ZC improved escape learning in the water maze. The two capital indicators of oxidative stress in brain homogenates, the amount of oxidized proteins (assessed as carbonyl group containing proteins) and lipid peroxidation, were significantly reduced in ZC treated animals. Thus, ZC, which had previously been shown to improve inhibitory avoidance learning and to have anxiolytic properties in adult animals, might also facilitate spatial learning in aged animals, and reduces indices of oxidative stress in brain tissue after chronic treatment.

Aging↗