Changes In Spontaneous Motor Activity Research Articles

Modified Effect of Peptide Preparations on Spontaneous Motor Activity in Male Rats under the Conditions of Light Desynchronosis

This study examined the effect of peptide extracts from the epiphysis-pituitary gland of Reindeer (Rangifer tarandus) and a delta sleep-inducing peptide, simulating a modified release of drugs, on the spontaneous motor activity of male rats under the conditions of light desynchronosis. The study revealed changes in spontaneous motor activity under the influence of extracts of a peptide nature and a delta sleep-inducing peptide under the following polar light regimes. Under the conditions of constant lighting and constant darkness, an increase and a decrease in activity was observed, respectively. Under normal lighting, peptide extracts showed increased efficacy. This method of pharmacological adjustment of the body’s circadian oscillators using modified-release peptides can be used to develop a scheme for correcting light desynchronosis.

Reduced intraepidermal nerve fibre density, glial activation, and sensory changes in HIV type-1 Tat-expressing female mice: involvement of Tat during early stages of HIV-associated painful sensory neuropathy.

HIV infection is associated with chronic pain states, including sensory neuropathy, which affects greater than 40% of patients. To determine the impact of HIV-Tat induction on nociceptive behaviour in female mice conditionally expressing HIV Tat1-86 protein through a doxycycline (DOX)-driven glial fibrillary acidic protein promoter, intraepidermal nerve fibre density and immune cell activation in the dorsal root ganglion (DRG) and spinal cord were assessed by immunohistochemistry. Mice were assessed for mechanical and thermal sensitivity for 9 weeks using von-Frey and Hargreaves tests. Intraepidermal nerve fibre density was significantly reduced after 6 weeks of Tat induction, similar to sensory neuropathy seen in clinical HIV infection. Tat induction through DOX caused a significant reduction in paw withdrawal thresholds in a time-dependent manner starting the 4th week after Tat induction. No changes in paw withdrawal latencies were seen in Tat(-) control mice lacking the tat transgene. Although reductions in paw withdrawal thresholds increased throughout the study, no significant change in spontaneous motor activity was observed. Spinal cord (cervical and lumbar), DRG, and hind paw skin were collected at 8 days and 6 weeks after Tat induction. HIV-Tat mRNA expression was significantly increased in lumbar DRG and skin samples 8 days after DOX treatment. Tat induced a significant increase in the number of Iba-1 positive cells at 6 weeks, but not after 8 days, of exposure. No differences in glial fibrillary acidic protein immunoreactivity were observed. These results suggest that Tat protein contributes to painful HIV-related sensory neuropathy during the initial stages of the pathogenesis.

Pyrethroid Based Mosquito Repellent Inhalation Induced Changes in Physical Activity in Albino Rats after Chronic Exposure

Introduction: The liquid vaporizers are very commonly used as residential insecticides in developing countries. Neurotoxic effects of pyrethroids have been reported earlier but study regarding its direct effect on physical activity of albino rats are scanty. So the present study was planned to assess and compare the effects of long term prallethrin (a Pyrethroid) exposure on albino rats. Method: Twenty albino rats were divided into two groups of control and experimental. Rats in experimental group were exposed to 3.2% w/v prallethrin vapours 12 hours daily for 180 days. Control animals were kept under identical conditions without exposure to said repellent. The albino rats in experimental group were subjected to Spontaneous Motor Activity, Forced Locomotor Activity and Swimming endurance test to record their physical activity. Result: Significant changes in Spontaneous Motor Activity, Forced Locomotor Activity and Swimming Endurance Test were not recorded in prallethrin exposed rats as compared to control ones throughout the study. Conclusion: Lack of changes in the behavioural parameters as seen in our study may be due to difference in the route adopted and perhaps due to limited duration of exposure and high degree of adaptability of the animal to adverse insults.

Profile of pharmacological effects of combination of buspirone with selected antidepressants: a behavioral study in mice

Background: Antidepressants are commonly prescribed drugs. Co-existing disorders like anxiety require therapy with other drugs. The profiles of pharmacological effects of these drugs on central nervous system are influenced by the administration of these drugs either as single or combination. This study is designed to observe the behavioral effects of antidepressants along with the antianxiety agent buspirone in mice. Methods: Four antidepressant drugs belonging to different groups are selected for the study. Amitriptyline, citalopram, venlafaxine and mirtazapine are given orally for 2 weeks. Subsequently, buspirone is added to each antidepressant drug for a period of 3 weeks. The behavioral effects in mice are observed at weekly intervals using photoactometer, rotarod, forced swim test and elevated plus maze. Results: The antidepressant drugs amitriptyline and citalopram showed any change in spontaneous motor activity recorded by photoactometer. In rotarod test venlafaxine showed an increase in values, which showed further increase when buspirone was added. In the forced swim test also, venlafaxine showed a different pattern of effects when compared to other antidepressants. In the elevated plus maze test, the four antidepressants did not show any increase in the time spent in open arm excepting citalopram. Venlafaxine showed an increase in time spent in closed arm. Conclusions: The test drugs do not show any significant depression of central nervous system at the dose used. Venlafaxine showed a different pattern of activity in the rotarod test and swim test. The variation in response is attributed to their effects on central neurotransmitter.

Bromocriptine Effect in Spontaneous Motor Activity Using Albino Mice

Bromocriptine is a potent agonist at the D2 receptor. The aim of this study is to investigate the bromocriptine effect in spontaneous motor activity, using variable doses with acute and subacute administration and variable onset of measurement using albino mice. Acute intraperitonealadministration of bromocriptine using doses of 0.625, 2.5, 5, and 10mg/kg and thecontrol group administration of 1% tween 80(n=7) were used. Spontaneous motor activity was scored after 30 and 60min of administration. Subacute administration is as follows:group1was administered 1% tween 80asa control and group2 was administered 10mg/kg bromocriptine. Spontaneous motor activity was scored using an open field test. Acute administration of bromocriptine after 30min (0.625 and 2.5mg/kg) did not show any significant changes in spontaneous motor activity while 5 and 10mg/kg produced a significant decrease. Acute administration of bromocriptine after 60min produced a significant decrease in spontaneous motor activity, with 0.625, 2.5, 5, and 10mg/kgdoses. Subacute administration of bromocriptine significantly increased spontaneous motor activity,compared to control. It is concluded that acute administration of bromocriptine at 30min decreased spontaneous motor activity, only with higher doses while its acute administration after 60min decreased spontaneous motor activity,with all doses (0.625, 2.5, 5, and 10mg/kg). As subacute administration increased spontaneous motor activity,these findings conclude that bromocriptine which produced its effect in spontaneous motor activityis time and dose dependence.

Neonatal exposure to propofol affects BDNF but not CaMKII, GAP-43, synaptophysin and tau in the neonatal brain and causes an altered behavioural response to diazepam in the adult mouse brain

Animal studies have shown that neonatal anaesthesia is associated with acute signs of neurodegeneration and later behavioural changes in adult animals. The anaesthetic effect of propofol is thought to be mediated by γ-amino butyric acid (GABA) A receptors. The present study investigated the effects on proteins important for normal neonatal brain development (i.e. BDNF, CaMKII, GAP-43, synaptophysin and tau), and adult spontaneous motor and anxiety-like behaviours in response to diazepam, after neonatal exposure to propofol. Ten-day-old mice were exposed to 0, 10 or 60 mg/kg bodyweight propofol. Neonatal propofol exposure changed the levels of BDNF in the brain, 24 h after exposure, but did not alter any of the other proteins. Neonatal propofol exposure significantly changed the adult response to the GABA-mimetic drug diazepam, manifest as no change in spontaneous motor activity and/or reduced sedative effect and an extinguished effect on the reduction of anxiety-like behaviours in an elevated plus maze. Although no adult spontaneous behavioural changes were detected after neonatal propofol exposure, the exposure caused an adult dose-dependent decrease in the response to the GABA-mimetic drug diazepam. These changes may be due to neonatal alterations in BDNF levels.

Stress-induced behaviour in juvenile rats: effects of neonatal asphyxia, body temperature and chelation of iron

Newborn mammals, showing reduced normal body temperature, might be protected against iron-mediated, delayed neurotoxicity of perinatal asphyxia. Therefore, we investigated the effects of (1) neonatal body temperature and neonatal critical anoxia as well as (2) postanoxic chelation of iron with deferoxamine, on open-field stress-induced behaviour in juvenile rats. The third aim of this study was to compare (after the above-mentioned treatments) circadian changes in spontaneous motor activity and body temperature in juvenile rats permanently protected from any stress. Neonatal anoxia at body temperature adjusted (both during anoxia and 2 h reoxygenation) to a level typical of healthy (37 °C) or febrile (39 °C) adults led to the stress-induced hyperactivity in juvenile (5–45 days old) rats. Both normal neonatal body temperature of 33 °C and chelation of iron prevented the hyperactivity in rats. Neither neonatal body temperature nor neonatal anoxia affected spontaneous motor activity or body temperature of juvenile rats, recorded in their home-cages with implantable transmitters. Circadian rhythmicity was also undisturbed. Presented data support the hypothesis that physiologically reduced neonatal body temperature can provide a protection against iron-mediated postanoxic disturbances of behavioural stress responses in juvenile rats.

Antihypertensive effect of docosahexaenoic acid in stroke-prone spontaneously hypertensive rats

Docosahexaenoic acid (DHA) is an n-3 unsaturated fatty acid derived from fish oils. The precise mechanisms of DHA actions are still obscure. Especially, the antihypertensive effect of DHA has not yet been elucidated. Stroke-prone spontaneously hypertensive rats (SHRSP) provide the best available model for essential hypertension and stroke. The present study was undertaken to elucidate the effects of long term administration of DHA on blood pressure and stroke-related behavior in SHRSP. The blood pressure of DHA-treated SHRSP was lowered significantly as compared with that of non-treated SHRSP. DHA produced an ameliorative effect on the decreased passive avoidance response in SHRSP. DHA also improved the behavioral changes in spontaneous motor activity of SHRSP. DHA-treated SHRSP produced a significant decrease in the levels of total cholesterol, low density lipoprotein, triglycerides, lipid peroxide, serum creatinine and blood urea nitrogen as compared with those in non-treated SHRSP. These findings indicate that the DHA-induced antihypertensive action may be associated with the amelioration of both serum lipid alteration and renal dysfunction in non-treated SHRSP. Moreover, DHA-treated SHRSP maintain the normal levels of acetylcholine and choline concentrations in the hippocampus and cerebral cortex. These findings demonstrated that DHA produced an ameliorative effect on cholinergic nerve dysfunction in SHRSP. The improved cholinergic nerve function induced by DHA might have an inhibitory effect on stroke-related behavior in SHRSP. The present study suggests that long term administration of DHA may suppress the development of hypertension and stroke-related behavioral changes in SHRSP.

Prenatal exposure to low concentrations of carbon monoxide alters habituation and non-spatial working memory in rat offspring

Inhalation of low concentrations (75 and 150 ppm) of carbon monoxide (CO) by pregnant rats from days 0 to 20 of gestation leads to alterations in habituation and working memory in young adult male offspring subjected to the novel exploration object test. In particular, lack of habituation upon the second presentation of the objects and failure in the ability to discriminate between the novel and the familiar object were found in CO (75 and 150 ppm)-exposed offspring. These alterations were not accompanied by changes in spontaneous motor activity (open field test). The subtle behavioral deficits observed in the present study have been produced by prenatal exposure to CO levels resulting in maternal blood carboxyhaemoglobin (HbCO) concentrations equivalent to those observed in human cigarette smokers.

Behavioral Effects of Dopamine Agonists and Antagonists: Influence of Estrous Cycle, Ovariectomy, and Estrogen Replacement in Rats

DÍAZ-VÉLIZ, G., M. S. BENAVIDES, S. BUTRÓN, N. DUSSAUBAT AND S. MORA, S. Behavioral effects of dopamine agonists and antagonists: Influence of estrous cycle, ovariectomy, and estrogen replacement in rats. PHARMACOL BIOCHEM BEHAV 62(1) 21–29, 1999.—The influence of the hormonal condition on the reactivity of central dopamine (DA) receptors was studied in male and in intact and ovariectomized (OVX) female rats. They were injected with selective DA agonists, acting either on D1 (SKF 38393, 2.5 or 10 mg/kg) or D2 receptors (PPHT, 31.3 or 125 μg/kg), or with selective DA antagonists, acting either on D1 (SCH 23390, 6.25 or 25 μg/kg), or D2 receptors (sulpiride, 10 or 40 mg/kg). The acquisition of an avoidance conditioning response (CAR) and the performance of some spontaneous motor behaviors were tested. Both D1 and D2 agonists and antagonists impaired the acquisition of CARs in diestrous, OVX, and male rats. Nevertheless, the effects of these drugs during estrus and in estradiol-primed OVX rats were different according to the drug and the dose injected. Whereas SKF 38393 failed to induce significative changes, PPHT and low doses of SCH 23390 and sulpiride improved the acquisition of CARS in those groups. The effects on conditioning were not accompanied with equivalent changes in spontaneous motor activity. Estradiol level fluctuations that occur in female rats within the estrous cycle or in OVX rats primed with estradiol would be responsive of changes in the response to DA agents. Although the reactivity of central DA systems is differentially affected by the hormonal condition of the rat, the precise mechanism of this modulatory action remains unknown.

Prenatal corticosterone treatment induces long-term changes in spontaneous and apomorphine-mediated motor activity in male and female rats

The potential influence of glucocorticoids on fetal brain development was investigated after corticosterone administration via pellets to pregnant rats during the last trimester of gestation. We examined both spontaneous motor activity and dopamine-mediated motor responses to apomorphine, a predominantly D 1 and D 2 receptor agonist, given at a postsynaptic dose (1 mg/kg, s.c.) to both prepubertal and adult male and female offspring. Prenatal corticosterone was found to produce the following alterations in the offspring: (1) Prepubertal stage: Male offspring: A statistically significant ( P<0.05) increase was observed in spontaneous rearing, motility and locomotion (activity measured during the first 30 min) without changes in apomorphine-induced motor responses. Female offspring: A reduction ( P<0.05) only in spontaneous rearing activity was observed during the exploratory phase (activity measured during the first 10 min) without significant changes in apomorphine-induced motor responses. (2) Adult stage: Male offspring: The exploratory activity to the novel environment was increased ( P<0.05) without significant changes in apomorphine-induced motor activity. Female offspring: An increase ( P<0.05) in spontaneous locomotion was observed during the first 30 min of testing without significant changes in exploratory activity to the novel environment. However, the apomorphine-induced motility and locomotion were reduced ( P<0.05) during the first 30 min. These observations indicate that prenatal corticosterone induces both short-term and long-term changes in spontaneous motor activity as well as long-lasting alterations in dopamine receptor response in the motor network mechanisms controlled by DA receptors. These changes are in part age and sex-dependent. The possible relationship between prenatal programming of the mesolimbic and nigrostriatal dopaminergic pathways by corticosterone and the observed changes in motor function is discussed.

Effect of oxotremorine on the acquisition of a conditioned avoidance response is modified by the estrous cycle, ovariectomy, and estradiol replacement in rats

This study was designed to evaluate the influence of the hormonal status of the rat on the effects of a potent reversible muscarinic agonist, oxotremorine, on the acquisition of conditioning avoidance responses (CARs) and the performance of some spontaneous motor behaviors. Oxotremorine (OXO 50 and 100 μg/kg, intraperitoneally) given 5 min before testing improved active conditioned avoidance in intact female rats at estrus and in ovariectomized rats after estradiol replacement, and impaired performance in female rats at diestrus and after ovariectomy without estradiol replacement. No significant differences due to hormonal status of the rat in some spontaneous motor behaviors were observed. In fact, OXO in this dose range failed to induce significant changes in spontaneous motor activity, the number of rears diminished, and the time spent in grooming behavior increased in all groups studied. These results provided behavioral evidence for the hypothesis that central cholinergic activity is function of the hormonal status of the animal. Relationships between ovarian hormones and cholinergic system are discussed.

Spectral analysis of body weight, food and water consumption and spontaneous motor activity in male Sprague-Dawley rats.

Spectral analyses by maximum entropy method were performed on the time-series data of body weight, food and water consumption and spontaneous motor activity in Sprague-Dawley rats. These parameters were recorded by a monitoring system collected every 30 min for 10 days. All the parameters had circadian (24 +/- 4 hr) and ultradian (less than 20 hr) rhythms. From the logarithmic transformation of spectral frequencies and their power spectral densities, the characteristics of the spectrum of body weight showed 1/f fluctuation and those of food and water consumption were white noises. The spectrum of the spontaneous motor activity showed complex characters. The range of frequencies lower than 0.1 Hz showed white noise while the range of those higher than 0.1 Hz were 1/f or 1/f2 fluctuations, especially in the range between 0.5 and 1.0 Hz (1-2 hours cycle). The auto-correlation coefficients of body weight did not declined suggesting that 24 hours cycle is only periodic phenomenon in body weight changes. Though the auto-correlation coefficients of food and water consumption also did not declined, they had not enough auto-correlations. This was consistent with the appearance of white noise in spectral analyses. The auto-correlation coefficients of spontaneous motor activity declined remarkably, and this suggests that there are various periodic changes in spontaneous motor activity including one to two hours cycles. These results suggest that the possibility of further extension of research is expected by using rhythmicity. It is also indicated that the time of measurement of body weight must be taken into consideration in experiments because of the presence of the circadian rhythmic changes.

Relationship between circadian changes in spontaneous motor activity and dorsal versus ventral striatal dopamine neurotransmission assessed with on-line microdialysis.

The relationship between circadian changes in spontaneous motor activity in rats and dopamine (DA) neurotransmission in the dorsal or ventral striatum was assessed with on-line in vivo microdialysis. The concentration of DA and DA metabolites in the dorsolateral caudate nucleus increased significantly at night. In contrast, DA in the nucleus accumbens did not change significantly across the light-dark cycle. The concentration of DA metabolites in the nucleus accumbens did show circadian variation, however, which was comparable with that seen in the dorsolateral caudate nucleus. Although there was a significant positive correlation between the concentration of DA in both the dorsal and ventral striatum and spontaneous nocturnal motor activity, the relationship was very weak, especially for the accumbens. This suggest that regulating the level of spontaneous motor activity per se is not a primary function of the mesostriatal DA system.

Relationship between circadian changes in spontaneous motor activity and dorsal versus ventral striatal dopamine neurotransmission assessed with on-line microdialysis.

Relationship between circadian changes in spontaneous motor activity and dorsal versus ventral striatal dopamine neurotransmission assessed with on-line microdialysis.

Effects of central administration of kynurenic acid on spontaneous locomotor activity in the kindled rat: A multivariate approach using the automated digiscan monitoring system

Changes in spontaneous motor activity in kindled hooded rats were measured following intracerebroventricular administration of three doses of kynurenic acid (65, 39, and 6.5 μg, dissolved in 3.3 μl isotonic saline). Behavior was measured in the automated Digiscan system on every third day during 13 days of drug administration to assess initial behavioral impairment and the development of tolerance. Activity data were collected beginning 5 min after drug administration for six consecutive 5-min samples. The results revealed a suppressive effect of central administration of kynurenic acid on the pattern of spontaneous locomotor activity and showed the development of behavioral tolerance. Initially, the degree of suppression was dose related, but as tolerance developed group differences were minimized. Most measures returned to predrug levels by day 13 except vertical movement, which remained suppressed in the 65-μg group throughout testing. This measure may have been more sensitive to the subtle and long-lasting motor impairments resulting from kynurenic acid.

Repeated lindane exposure in the rat results in changes in spontaneous motor activity at 2 weeks post-exposure

Male Wistar rats were given 25 doses of lindane, 10 mg/kg per day, 1 ml/kg p.o. in olive oil. or control vehicle. Two weeks after the last dose, the animals were assessed for modifications in spontaneous motor activity, plus-maze behavior, shuttle-box active avoidance acquisition, brain regional concentrations of biogenic amines and metabolites, and regional [ 35S]TBPS binding. Rats treated with lindane showed an increase in spontaneous motor activity. Although no additional behavioral or neurochemical modifications were found, the changes in activity observed at 2 weeks post-exposure further demonstrate the need to assess lor long lasting neurobehavioral sequelae of repeated lindane exposure.

Apparent enhancement by SCH 23390 of apomorphine-induced locomotor activity in mice

Effects of the dopamine (DA) D 1 antagonist SCH 23390 and the DA D 2 antagonist (−)-sulpiride on apomorphine-induced characteristic changes in spontaneous motor activity were investigated in mice using the system we have devised for automatically analyzing animal behaviors in mice. Apomorphine (3 mg/kg, SC) markedly increased parameters of spontaneous motor activity such as locomotor activity and rearing time. Apomorphine-induced increase in locomotor activity had peaks at 5–20 and 30–50 min after administration, and its trough was closely related to the marked increase in rearing time induced by this agonist. Apomorphine-induced locomotor activity accumulated over a 40-min period from 5 to 45 min after apomorphine injection, during which apomorphine-induced increase in rearing time peaked, was significantly increased by intraperitoneal administration of 0.03 and 0.1 but not 0.01 mg/kg SCH 23390. Apomorphine-induced increase in rearing time was dose-dependently depressed by this antagonist. In contrast, (−)-sulpiride (10–40 mg/kg, IP) decreased apomorphine-induced increases in rearing time and locomotor activity rather than enhancing the latter parameter. These data suggest that the apparent enhancement by SCH 23390 of apomorphine-induced locomotor activity is mediated through DA D 1 receptors and does not always correlate with depression of apomorphine-induced rearing behavior in mice.

Methamphetamine- and apomorphine-induced changes in spontaneous motor activity using a new system to detect and analyze motor activity in mice

A new system was devised to detect animal spontaneous motor activity in more detail, and methamphetamine- and apomorphine-induced changes in spontaneous motor activity were analyzed using this system. The system consists of a doughnut-shaped cage with 36 units of detectors. Scanning of each detector unit was three-dimensionally carried out, and then scanning data were fed into a personal computer. These steps were completed within 0.1 sec and repeated. Spontaneous motor activity was analyzed as changes in parameters, such as total activity, locomotor activity, vertical activity (the number of rearings and the rearing time), motion time, and average speed. Regarding dependence on the dosages of methamphetamine and apomorphine, the time courses of changes in total activity and locomotor activity markedly differed from those for changes in vertical activity. Changes in the numbers of rearings and rearing time induced by 2 mg kg methamphetamine peaked 40–80 min after administration, whereas those in other parameters did so 15–25 min after. Three mg kg apomorphine-induced changes in total activity and locomotor activity showed two peaks 10–15 and 40–50 min after administration, respectively. At the same dosage, apomorphine markedly increased rearing time with slight but not significant effects on the number of rearings. These effects peaked 20–30 min after administration. These results indicate this system to be quite useful to detect and analyze drug-induced changes in spontaneous motor activity.

マウス運動量の測定及び解析のための新しいシステム ５種の中枢興奮薬の作用

To estimate the spontaneous motor activity in mice, a new system with highly stable sensitivity and good reproducibility was made, and the effects of five central stimulants were investigated. The apparatus consists of a doughnut-shaped cage with detectors for measuring spontaneous motor activity; i.e., the number of movements, vertical activity, total distance, etc., for every five min. Methamphetamine (0.5, 1 and 2 mg/kg, s.c.) produced an increase in the number of movement and markedly increased total distance. Cocaine (20, 50 and 75 mg/kg, s.c.) caused a marked increase in movement and total distance. Mice injected with 50 mg/kg of cocaine showed long-lasting locomotion with few stops throughout the observation period. Caffeine (10, 30 and 100 mg/kg, s.c.) produced a long-lasting and moderate excitation. Morphine (5, 10 and 20 mg/kg, s.c.) caused a marked increase in continuous locomotion dose-dependently. Apomorphine produced a transient increase in rearing and locomotion at a dose of 1 mg/kg, s.c.; and it produced long-lasting rearing and moderate locomotor activity at 3 mg/kg. These results suggest that this apparatus is able to detect characteristic changes in spontaneous motor activity produced by central stimulants and may be useful for analyzing drug-induced motor activity in mice in more detail.