Locomotor Activity Of Wistar Rats Research Articles

Effects of ELF-PEMF exposure on spontaneous alternation, anxiety, motor co-ordination and locomotor activity of adult wistar rats and viability of C6 (Glial) cells in culture

The effects of ELF-PEMF exposure on spontaneous alternation, anxiety, motor coordination, and locomotor activity have been discussed in various pre-clinical and clinical settings. Several epidemiological and experimental studies have demonstrated the potential effects of ELF-PEMF when exposed > ∼1 h/day; however, very few studies have focused on understanding the influence of ELF-PEMF exposure of 1–3 mT with an exposure duration of < 1 h/day on spontaneous alternation, anxiety, motor coordination, and locomotor activity. Hence, we attempted to study the effects of ELF-PEMF exposure of 1–3 mT, 50 Hz with an exposure duration of 20 min each with a 4 h gap (2 times) on the cellular proliferation and morphologies of C6 (Glial) cells and spontaneous alternation, anxiety, motor coordination and locomotor activity of Wistar rats under in vitro and in vivo conditions, respectively. The results showed that ELF-PEMF exposure did not induce any significant levels of cellular fragmentation and changes in the morphology of glial cells. Also, the outcomes revealed no noticeable effects on spontaneous alternation, anxiety, motor coordination, and locomotor activity in PEMF-exposed groups compared with the control. No undesirable side effects were observed at the highest dose (B=3 mT). We also performed histological analysis of the selected brain sections (hippocampus and cortex) following ELF-PEMF exposure. Incidentally, no significant changes were observed in cortical cell counts, tissue structure, and morphology.

Effects of a semi-chronic exposition to Paraquat and Maneb on the circadian rhythm of locomotor activity in Wistar rats

Effects of a semi-chronic exposition to Paraquat and Maneb on the circadian rhythm of locomotor activity in Wistar rats

Impact of a novel environment on alcohol-induced locomotor activity in Wistar rats.

Clinical studies have shown a positive correlation between novelty-seeking behavior and the susceptibility to consume drugs of abuse. Although several animal studies have demonstrated this correlation with psychostimulants or morphine, studies with alcohol have shown conflicting results. The aim of this work was to investigate alcohol-induced motor effects in Wistar rats with different responses to novelty. Animals were classified as Low- (LR) or High-Responders (HR) to novelty, depending on their horizontal activity in an automated open field. Motor activity was recorded in naïve, saline, and alcohol-administered rats at different doses (0.1, 0.25, 0.5, 1.0, or 2.5g/kg). Horizontal movements, rearings, and stereotyped behaviors were evaluated. After the behavioral test, animals were sacrificed and blood alcohol concentrations (BACs) were measured. Low (0.1 and 0.25g/kg) and high (2.5g/kg) alcohol doses decreased horizontal movements in LR animals, whereas 1.0g/kg increased this parameter in HR rats. Rearings were increased by alcohol 1.0g/kg in LR animals. In HR rats, alcohol doses of 0.5 and 1.0g/kg also increased this parameter. Stereotyped behaviors were decreased by an alcohol dose of 2.5g/kg in LR animals, but were increased by an intermediate dose (1.0g/kg) in HR rats. Differences in horizontal movements and rearings were found between LR and HR animals at certain ethanol doses. Horizontal movements (0.25g/kg) and rearings (0.5g/kg) were lower in LR than HR rats; however, rearings were lower in HR than LR rats at 1.0g/kg. BACs were similar between LR and HR rats at all ethanol doses. These findings suggest that HR rats are more responsive to the stimulant effects of intermediate alcohol doses, whereas LR animals are sensitive to low/high doses of the drug. Sensitivity to alcohol motor effects may substantially depend on the initial animal's response to a novel environment. The stimulant effects of alcohol may constitute important behavioral traits significantly associated with the rewarding properties of the drug.

Delayed Behavioral Effects of SH–I–048A, a Novel Nonselective Positive Modulator of Gabaa Receptors, After Peripheral Nerve Injury in Rats

Abstract The complex clinical picture of mono-neuropathy following injury of peripheral nerve is often accompanied by changes in the patients’ affective states. It has been shown that positive allosteric modulators of GABAA receptors can decrease nociceptive transmission in animal pain models. However, recent findings suggest a possibility that at least some of the antinociceptive effects of benzodiazepines, related to neuropathic painful stimuli, may to a significant degree be a consequence of their anxiolytic action. In this study we evaluated the possible delayed effects of SH-I-048A, a newly- synthesized high-efficacy nonselective positive modulator of GABAA receptors, on anxiety-like behavior and locomotor activity in Wistar rats with a previously induced peripheral nerve injury. Assessment of behavioral parameters, using spontaneous locomotor activity and elevated plus maze tests, was performed 48h after completion of single-day threei. p. injections treatment consisting of zero, one, two or three doses of SH-I-048А (10 mg/kg). In general, rats’ behavior observed 72 h after a moderate peripheral nerve injury did not indicate the persistence of sequelae of mono-neuropathic pain. The rats treated with three doses of SH-I-048А displayed an enhanced immobility time in the locomotor activity test, without concomitant decrease of the total distance traveled. On the other hand, in the group treated with two doses of SH- I-048А, a decrease in the emotional reactivity in the elevated plus maze test was observed. Subtle changes in the regimen of dosing of SH-I-048А affect locomotor activity and anxiety-related behavior in animals with peripheral nerve injury.

Effect of angiotensin II on rhythmic per2 expression in the suprachiasmatic nucleus and heart and daily rhythm of activity in Wistar rats

Endogenous daily rhythms are generated by the hierarchically organized circadian system predominantly synchronized by the external light (L): dark (D) cycle. During recent years several humoral signals have been found to influence the generation and manifestation of daily rhythm. Since most studies have been performed under in vitro conditions, the mechanisms employed under in vivo conditions need to be investigated. Our study focused on angiotensin II (angII)-mediated regulation of Per2 expression in the suprachiasmatic nuclei (SCN) and heart and spontaneous locomotor activity in Wistar rats under synchronized conditions. Angiotensin II was infused (100ng/kg/min) via subcutaneously implanted osmotic minipumps for 7 or 28days. Samples were taken in 4-h intervals during a 24hcycle and after a light pulse applied in the first and second part of the dark phase. Gene expression was measured using real time PCR. Locomotor activity was monitored using an infrared camera with a remote control installed in the animal facility. Seven days of angII infusion caused an increase in blood pressure and heart/body weight index and 28days of angII infusion also increased water intake in comparison with controls. We observed a distinct daily rhythm in Per2 expression in the SCN and heart of control rats and infused rats. Seven days of angII infusion did not influence Per2 expression in the heart. 28days of angII treatment caused significant phase advance and a decrease in nighttime expression of Per2 and influenced expression of clock controlled genes Rev-erb alpha and Dbp in the heart compared to the control. Four weeks of angII infusion decreased the responsiveness of Per2 expression in the SCN to a light pulse at the end of the dark phase of the 24hcycle. Expression of mRNA coding angiotensin-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2) showed a daily rhythm in the heart of control rats. Four weeks of angII infusion caused a decrease in amplitude of rhythmic expression of Ace, the disappearance of rhythm and an increase in Ace2 expression. The Ace/Ace2 ratio showed a rhythmic pattern in the heart of control rats with peak levels during the dark phase. Angiotensin II infusion decreased the mean Ace/Ace2 mRNA ratio in the heart. We observed a significant daily rhythm in expression of brain natriuretic peptide (BNP) in the heart of control rats. In hypertensive rats mean value of Bnp expression increased. Locomotor activity showed a distinct daily rhythm in both groups. Angiotensin II time dependently decreased ratio of locomotor activity in active versus passive phase of 24hcycle. To conclude, 28days of subcutaneous infusion of angII modulates the functioning of the central and peripheral circadian system measured at the level of Per2 expression and locomotor activity.

The role of cortical serotonin in anxiety and locomotor activity in Wistar rats.

The brain's serotonergic system is known to play an important role in the modulation of anxiety. While the role of serotonin (5-HT) in subcortical structures is well investigated, little is known about the function of cortical 5-HT. The present series of studies used local injections of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), into the medial prefrontal cortex (mPFC), entorhinal cortex (EC), or occipital cortex (OccC) of rats to chronically reduce 5-HT neurotransmission in these brain areas. The animals were tested for anxiety-like behavior on the elevated plus-maze and open field. An 82% depletion of 5-HT from the mPFC increased anxiety-like behavior, while no general motor effects were evident. In contrast, a 63% 5-HT-depletion of the EC or a 78% 5-HT-depletion of the OccC did not have any effects on emotional or exploratory behaviors. These findings are in line with a proposed role of 5-HT in the mPFC in the modulation of anxiety- and stress-mediated behavior and demonstrate a functional differentiation between different cortical 5-HT projections.

Cataleptic activity of the denatured venom of the social wasp Agelaia vicina (Hymenoptera, Vespidae) in Rattus norvegicus (Rodentia, Muridae)

Catalepsy is a state of immobility, commonly experienced by patients with chronic use of many antiparkisonism and neuroleptic drugs. Recently, catatonia has been considered as an evolutionary-based fear response. The cataleptogenic effects of the low molecular weight compounds from the venom of the social wasp A. vicina (AdAv) were reported in rodents. Intracerebroventricular injections of AdAv in highest dose reduced the locomotor activity of Wistar rats in the open field and induced ataxia and catalepsy within 10 min. This effect could be observed up to 30 min after injections. Lower doses of denatured venom injected in brain ventricles also reduced the locomotor activity of the rats but did not induce catalepsy. The cataleptic effects of the intracerebrally administered AdAv were antagonized by the peripheral (intraperitoneal) pretreatment with theophylline and ketamine. Moreover, the central effects of the AdAv were compared to those elicited by the neuroleptic drug haloperidol (intraperitoneally administered), whose cataleptic effects were also antagonized by theophylline and ketamine. However, the association of haloperidol and denatured venom was reverted by theophylline but not by ketamine. These findings suggest that A. vicina venom may affect neural substrates involved with catalepsy in the central nervous system.

Efffects of vigabatrin on spontaneous locomotor activity of rats

AbstractEffects of vigibatrin (saline, 125, 250, or 500 mg/kg i.p.) on spontaneous locomotor activity in Wistar rats were investigated. There was a dose dependent decrease in amount of locomotion for doses up to 250 mg/kg. This decrease was measurable 2–4 hours after injection and still became more pronounced in the following hours. The mean velocity during the movements 2–6 hours after injection remained intact and was higher in the 500 mg/kg group. In this high dose group an abnormal posture with a hunched back and pilo‐erection was observed. The decrease of the amount of motor activity with the preservation of the mean velocity in this non‐stimulating procedure, suggests that the level in which the experimental procedure imposes motor activity might be an important factor when measuring effects of vigabatrin. Postscript: Immediate post injection effects were observed, equivalent to those seen in the writhing test, a pain test using hyperosmolar saline injections. These observations stress the importance of controlling the osmolarity of the injection fluids.

Effects of thyroid hormone deficiency on behavior in rat strains with different predisposition to catalepsy

The effects of thyroidectomy on anxiety-related behavior in the elevated plus-maze test, locomotor activity, and defecation in the open-field test and duration of cataleptic freezing were studied in rats of two strains differing in predisposition to catalepsy: cataleptic strain GC and its ancestor strain Wistar. Total thyroxine level was significantly decreased in control GC rats compared to that in control Wistar rats. Control Wistar and GC rats did not differ either in the percentages of open-arm entries or the time spent therein in the elevated plus-maze test or in defecation score in the open-field test. At the same time, control Wistar rats showed more locomotor activity compared to control GC rats in the open-field test. Thyroid hormone deficiency did not affect the percentages of open-arm entries and the time spent therein in the elevated plus-maze test as well as defecation score in both strains. Thyroidectomy did not alter significantly locomotor activity in Wistar rats, but produced a nearly twofold increase in locomotor activity in GC rats. The most important finding is that thyroidectomy significantly increased the expression of catalepsy in Wistar rats, which points to a role of thyroid hormones in the regulation of predisposition to cataleptic reaction.

Effect of Olivocochlear Bundle Lesion on Locomotor Activity in Rats

HSIEH, Y.-L., T.-J. CHEN, C.-H. LIN AND S.-S. CHEN. Effect of olivocochlear bundle lesion on locomotor activity in rats. Physiol Behav 64(2) 179–184, 1998. This study was conducted to investigate the effect of olivocochlear bundle (OCB) lesion on spontaneous locomotor activity in Wistar rats. The OCB is an auditory efferent pathway which originates from the superior olivary complex in the brainstem and terminates within the cochlea. It has an inhibitory effect on the auditory end organs. In the present study, the OCB was damaged at the floor of the fourth ventricle using radiofrequency current. The rats’ locomotor activities were then monitored weekly for 2 months using an automated Digiscan activity monitor system. Six behavioral variables were collected and analyzed: horizontal activity (HA), total distance (TD), movement time (MT), vertical activity (VA), stereotypy count (SC), and margin time (MGT). Significant time-dependent increases were noted for HA, TD, VA, and SC following OCB lesion. These results of increasing exploratory and stereotyped behaviors may be caused by the rat experiencing more auditory stimulation than before due to OCB dysfunction and may cause the rat to become more curious to explore its surroundings.

Effect of tetrabenazine and α‐methyl‐m‐tyrosine on exploratory activity and brain catecholamines in rats

1. Spontaneous exploratory locomotor activity of Wistar rats was measured in photocell activity cages, and brain noradrenaline (NA) and dopamine (DA) were determined fluorometrically after ion exchange purification.2. Tetrabenazine (TBZ) (10 mg/kg) produced a fall in NA and DA concentrations in rat brain stems which was correlated with the fall in activity in female Wistar rats.3. alpha-Methyl-m-tyrosine (alphaMMT) reduced the concentration of rat brain NA without affecting DA concentration or activity.4. Pretreatment with alphaMMT did not stop TBZ from producing a marked reduction in activity and NA concentration, but partially protected DA from the depleting action of TBZ.5. These results support a role for catecholamines in the control of motor activity, but they do not implicate NA more than DA and they emphasize that the mechanism by which drugs affect the concentrations of catecholamines may be more important than the gross concentrations attained.