SEARCH · Search PubMed

Results for “Exploratory Behavior”

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.

SourceResearch connectionFrom yearThrough year

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

At least 181 records · Page 10Linked to original sources

PubMed2003

A synthetic peptide ligand of NCAM affects exploratory behavior and memory in rodents.

The neural cell adhesion molecule (NCAM) is an important modulator of neuronal development and plasticity associated with learning and memory. Previously, a synthetic peptide ligand of NCAM, called C3, has been identified and shown to modulate neuronal plasticity in vitro and memory in a step-through passive avoidance task in rats in vivo. In this study, we extended these findings and found that intraventricular injection of C3 prior to training impaired learning or memory processes in rats and mice in an approach avoidance task and decreased exploratory behavior in rats. The effect of C3 was additionally evaluated in the Morris water maze; memory impairment was observed in the second training trial 24 h after the injection of C3 only, indicating an effect on short-term memory. The C3-mediated memory impairment observed in the approach avoidance and water maze tests is suggested to be the result of C3-inhibiting NCAM functions in the brain. This study demonstrates that it is possible to modulate learning/memory processes in rodents in vivo with small synthetic NCAM-binding peptides that induce developmental plasticity in vitro.

Animals↗

PubMedDate not supplied

Exploratory behavior and locomotor activity: a failure to find effects in animals prenatally exposed to cocaine.

Pregnant Long-Evans rats were administered cocaine orally (60 mg/kg) on gestational days 14-21, or subcutaneously (40 mg/kg) on gestational days 8-21. The oral dosage of cocaine produced some maternal lethality and reduced maternal weight gain throughout the pregnancy by approximately 12%. The subcutaneous dosage regimen reduced the lethality but still caused a decrease in maternal weight gain. Neither dosing regimen affected the number of pups in the litter, their weight, or growth. The offspring of dams that received the oral dosage were examined as adults in an automated holeboard apparatus and were also tested at postnatal day 21 and as adults in an open field. Adult animals exposed prenatally to cocaine did not differ from untreated controls in any of the automated measures of the holeboard apparatus or in the various behaviors, including nosepokes, recorded in the open field. Animals in the vehicle control group did make fewer nosepokes in the open field than the cocaine group, which did not differ from untreated animals. The offspring of dams given the subcutaneous dosage regimen were observed in the open field at day 21. In this case, the prenatal cocaine group had a tendency to make fewer crosses into adjacent quadrants, to rear less often, and to make fewer nosepokes than the control groups. Based on these and other data from our lab, it does not appear that in the rat, prenatal cocaine exposure has pronounced effects on subsequent exploratory behavior and activity in weanling or adult animals.

Administration, Oral↗

PubMed2005

Effects of postweaning undernutrition on exploratory behavior, memory and sensory reactivity in rats: implication of the dopaminergic system.

The effects of early undernutrition on behavior and brain biochemistry were examined in rats. At weaning, rats were provided either an ad lib diet (control group) or maintained at 80% of the weight of their control littermates (undernourished group). Three weeks into the diet they were tested in an open field. After 6 weeks of diet, HPLC analyses were conducted on sample brains from each group to assess levels of dopamine and metabolites, respectively dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum. At seven weeks of diet, remaining rats were trained in an 8-arm radial maze, and a retention test conducted 72 h after attaining the learning criterion. At fourteen weeks of diet, sensory reactivity was measured by tail-immersion in a water bath maintained at constant temperature 50 +/- 1 degrees C. Undernourished rats exhibited hyperactivity and increased exploratory behavior in the open field, as well as increased sensory reactivity in the tail flick test. In the radial maze, however, undernourished rats did not differ from controls in either learning or retention. Haloperidol (i. p. injection) impaired retention by control but not undernourished animals. HPLC analyses showed an increase in dopamine turnover in the striatum of undernourished rats. Our results suggest that, unlike its effects when induced immediately at birth or in adulthood, undernutrition at weaning does not appear to influence learning and retention but induced an hyperactivity and alterations in striatal DA turnover which was associated with a decrease in responsiveness to i. p. haloperidol injection.

Animals↗

PubMed1989

Corticotropin-releasing factor modulates defensive-withdrawal and exploratory behavior in rats.

The role of corticotropin-releasing factor (CRF), an endogenous neuropeptide, in modulating species-typical responses was examined in an unfamiliar open field containing a small chamber. Rats placed in this small chamber spent most of their time withdrawn in it. However, rats given an intracerebroventricular injection (20 micrograms) of alpha-helical CRF(9-41), a CRF receptor antagonist, emerged from the chamber and explored the unfamiliar open field. Additional studies showed that after 1 exposure to the test environment, vehicle-treated rats increased their time spent in the open field and returned intermittently to the chamber. This result suggests that reexposure reduces the threatening impact of an unfamiliar open field. Importantly, CRF (300 ng) injected centrally, but not peripherally, before reexposure to the test environment significantly reduced exploration in the open field and increased a pattern of defensive-withdrawal into the chamber. Data suggest that whether defensive-withdrawal or exploratory behavior is exhibited may depend on CRF actions in brain systems that mediate the perception of threat in the environment.

Animals↗

PubMed1998

Neuronal overexpression of heme oxygenase-1 correlates with an attenuated exploratory behavior and causes an increase in neuronal NADPH diaphorase staining.

Heme oxygenase isozymes, HO-1 (also known as hsp32) and HO-2, are the source for the formation of the putative messenger molecule carbon monoxide (CO), reactive iron, and the in vitro antioxidant bilirubin. We have developed and characterized transgenic (Tg) mice that overexpress the stress protein in neurons in various brain regions. The Tg mice were generated by the use of rat HO-1 cDNA under the control of the neuron-specific enolase promoter. Except for a tendency to have an enlarged spleen, Tg mice did not show gross anatomical changes. Increase in HO-1 mRNA, which was demonstrated by northern blot analysis and in situ hybridization, was accompanied by an increase in neuronal HO-1 protein expression, shown by immunohistochemistry and western blotting, and an increase in HO activity. Expression of the transgene correlated with an attenuation of exploratory behavior and increased circling activity and coincided with enhanced neuronal NADPH diaphorase staining. Those changes were not accompanied by an increase in DNA damage or significant change in whole-brain NO synthase activity. The HO-1 Tg mice potentially represent a good model to examine the function of CO as a neuromodulator, iron as a gene regulator, and bile pigments as in vivo antioxidants.

Animals↗

PubMed1992

The role of histamine in the anterior hypothalamus and its functional interaction with the hippocampus on exploratory behavior in adult male rats.

The possible effects of histamine (HA) locally applied into the preoptic area (POA) on hippocampus-mediated behaviors were studied in adult male rats. Animals were double-implanted unilaterally with microinjection cannulae into POA and hippocampus (HPC). In experiment 1, HA was injected into POA and pyrilamine (H1-HA antagonist) or ranitidine (H2-HA antagonist) were microinjected into the ipsilateral HPC in two different doses. In Experiment 2, HA was injected into POA and the histamine antagonists were microinjected into the contralateral HPC. Ten min later the animals were tested in an automatic monitor activity. Horizontal, ambulatory and vertical movements were measured as general motor exploratory behaviors. Contact time (in seconds) to a circular metal rack positioned in the center of the animal activity monitor was also recorded as goal-directed exploratory activity. Results of Experiment 1 showed that HA in POA exerted an inhibitory influence on general motor behaviors and also on goal-directed activity. Ipsilateral administration of HA-antagonists into HPC blocked the HA effect on behavior. Results of Experiment 2 showed that the administration of the HA-antagonists in any of the two doses used were not able to block the depressive actions on behavior caused by HA into POA. In conclusion, data suggest that POA is linked to the ipsilateral HPC through histaminergic influence to control behavioral patterns induced by novelty.

Animals↗

PubMed2003

Putative anxiety-linked effects of the nitric oxide synthase inhibitor L-NAME in three murine exploratory behavior models.

The aim of the current study was to extend investigation into possible linkage between nitric oxide (NO) and anxiety-linked behavior using a battery of tests. Effects of the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) were investigated in three murine models of anxiety-the light-dark, hole-board and elevated plus-maze-in between-groups designs. Treatment groups included L-NAME (0 [vehicle, or Veh], 10, 25, and 50 mg/kg) and 50 mg/kg of the inactive isomer N(G)-nitro-D-arginine methyl ester (D-NAME) injected subcutaneously. Mice exhibited a robust anxiogenic-like response profile reflected by dose-related decreases in both light-dark (transitions and time in lighted area) and hole-board (head dips and time spent head dipping) test measures, reaching statistical significance at 25 and 50 mg/kg L-NAME when compared to Veh controls (P<.05 or.01; Dunnett's t test), while distance traveled and rearing showed no significant differential pattern in either model. In both models, there was a strong dissociation between nonspecific locomotion and putative exploratory behaviors. D-NAME was not significantly different from Veh condition in either model, indicating a stereospecific action and supporting NO involvement. A dose-related decrease was also observed for several traditional and ethological measures in the plus-maze; however, the effect was limited and relatively weak or absent; with the exception of open-arm and percent open-arm entries, putative anxiety-sensitive measures reached statistical significance only at the highest dose. Reductions in motor activity compromised ability to dissociate an anxiety linkage from a nonspecific motor effect in most measures. It is concluded that the hole-board and light-dark tests provide indication of anxiogenic-like action of NOS inhibition, suggesting that NO has an anxiolytic action. Data from the plus-maze are unclear, owing to a confounding motor influence in most measures.

Animals↗

PubMed1957