Exploratory Activity In Mice Research Articles

Behavioral effects of the aqueous extract of Guiera senegalensis in mice and rats.

Behavioral effects of the aqueous extract of Guiera senegalensis on the central nervous system of mice and rats were investigated. Spontaneous motor activity, pentobarbital sleeping time, amphetamine-stereotyped behavior, exploratory activity and performance on treadmills (rota-rod) were evaluated. The results revealed that the aqueous extract of G. senegalensis reduced spontaneous motor activity in mice, prolonged the duration of pentobarbital sleeping time in rats and attenuated amphetamine-induced stereotype behavior in rats. The extract also decreased exploratory activity in mice and had no observable effects on motor coordination (rota-rod) at the doses tested. The results suggested that the crude aqueous extract of G. senegalensis possesses some biologically active principles that are sedative in nature.

Pharmacological Studies On Sterculia Foetida Leaves

An alcoholic extract of Sterculia foetida L. leaves was subjected to pharmacological screening using various animal models. The extract caused reduced exploratory activity in mice. Further it potentiated pentobarbitone sleeping time in normal and chronic pentobarbitone-treated mice. It also potentiated barbital sodium-induced hypnosis, indicating central nervous system depressant activity. The extract also exhibited significant antiinflammatory activity in the acute carrageenan-induced rat paw edema and the chronic granuloma pouch models. However, it was devoid of analgesic activity in the tail flick model.

Effects of several amnesic drugs on the habituation of exploratory activity in mice as indexed by horizontal and vertical activities

1. 1. The effects of several drugs on the habituation of exploratory activity in mice were investigated by using animal movement analyzing systems which could detect horizontal and vertical activities. 2. 2. Habituation was regarded as the difference between exploratory activity measured first (session 1) and that measured second (session 2). 3. 3. Scopolamine (1, 3 and/or 6 mg/kg), pirenzepine (20 and 40 μg) injected immediately after session 1, cycloheximide (30 mg/kg), diazepam (1, 2 and/or 4 mg/kg) and dizocilpine (0.05, 0.1 and/or 0.2 mg/kg), unlike butylscopolamine (1, 3 and 6 mg/kg) or haloperidol (0.2 and 0.4 mg/kg), significantly increased horizontal activity but not always vertical activity in session 2. 4. 4. From the results obtained, it appears that the increase in horizontal activity in session 2 is more appropriate as an indicator of the impairments of memory processes than that in vertical activity.

Antidepressant activity of S-adenosyl-L-methionine in mice and rats.

S-Adenosyl-L-methionine (SAM), main methyl donor, was tested in mice and rats in several models which are predictive of possible antidepressant activity. In the forced swimming test in rats the effect of SAM was compared with that of the tricyclic antidepressant amitriptyline. SAM decreased dose-dependently immobility time in the forced swimming test in mice and rats, these effects being antagonized by haloperidol and prazosin (the latter only in rats). Locomotor or exploratory activity in mice and rats was not increased by SAM. D-Amphetamine-induced locomotor hyper-activity in rats was increased by repeated (14 days, twice daily) treatment with SAM. Behavioural stimulation induced by D-amphetamine or L-dopa (given with benserazide) in mice was not changed by a single dose of SAM. The drug reduced hypothermia induced by apomorphine in mice. Hypothermia induced by reserpine or clonidine in mice was not antagonized. SAM increased the amplitude of the acoustic startle reflex. The above results indicate that the psychopharmacological profile of SAM resembles that of antidepressants in only some tests. The mechanism by which SAM produces its antidepressant effect needs further investigation.

P-232 - Effects of different drugs on the habituation of exploratory activity in mice

P-232 - Effects of different drugs on the habituation of exploratory activity in mice

Exposure to Strong Static Magnetic Fields Induces Hypoactivity in Weaning Mice

We studied the effects of a prolongued exposure to a strong (1.0 Tesla) static and uniform magnetic field upon the open field behaviour and body weight of weaning mice. We observed a marked reduction in the exploratory activity of mice exposed to the field relative to that of control animals kept in similar surroundings, and handled in the same way as the exposed mice. One week of continuous exposure to a 1.0 T field significantly reduces peripheral square entries (p<0.01) as well as rearings (p<0.05), but has no effect on body weight. Our findings agree with the suggestion that a strong magnetic field may act as stressing agent.

Anxiogenic-like action of caerulein, a CCK-8 receptor agonist, in the mouse: influence of acute and subchronic diazepam treatment

Effects of caerulein, a cholecystokinin octapeptide (CCK-8) receptor agonist, on exploratory activity of mice were investigated. Exploratory and locomotor activity of animals were measured using elevated plus-maze and open field tests. The systemic administration of caerulein at non-sedative doses (100 ng/kg-1 micrograms/kg i.p.) resulted in a significant decrease in the exploratory activity of mice. This effect was completely blocked by proglumide, a CCK-8 receptor. Acute treatment with low doses (0.1-0.75 mg/kg i.p.) of diazepam did not attenuate the anxiogenic-like effect of caerulein, but at more high doses of diazepam the coadministration depressed locomotor activity in mice. After subchronic diazepam treatment (2.5 mg/kg once a day, 10 days, i.p.) tolerance was developed toward the sedative effect of diazepam, and 72 h after withdrawal of the drug the animals showed increased anxiety in the plus-maze test. 30 min after the last injection procedure the anxiogenic-like effect of caerulein (500 ng/kg i.p.) on exploration was absent in both diazepam or vehicle groups. However, 72 h after the last pretreatment injection caerulein (500 ng/kg i.p.) reduced significantly the exploratory activity in control group, whereas it was inactive after diazepam withdrawal. The results obtained in this study support the hypothesis that endogenous CCK-8 an CCK-8 receptors are involved in the neurochemistry of anxiety and the anxiolytic action of benzodiazepine tranquillizers.

Habituation of exploratory activity in mice: Effects of combinations of piracetam and choline on memory processes

The effects of various piracetam + choline combinations on an experimental model of memory were investigated. Mice were given two sessions in a simple photo-cell activity cage and the decrease in activity at the second session (habituation) served as an index of retention. Retention was facilitated by post-session administration of 2000 mg/kg piracetam IP and 50 mg/kg piracetam + 50 mg/kg choline IP. Similar injections of choline alone (10 to 200 mg/kg IP), piracetam alone (10 to 1000 mg/kg IP) or other combinations of piracetam and choline were without effect. These results, consistent with those reported elsewhere, suggest that piracetam can interact with choline to facilitate memory processes in mice.

Habituation of exploratory activity in mice as a model of memory: Pharmacological evidence

Habituation of exploratory activity in mice as a model of memory: Pharmacological evidence

Further characterization of a simple, automated exploratory model for the anxiolytic effects of benzodiazepines

Anxiolytics specifically increase the number of exploratory transitions in a two-chambered model system for anxiety in mice. Characterization of parameters to optimize and standardize this model required analysis of multiple use of test animals, intertrial interval, and circadean variability. Time of day did not affect exploratory activity in mice treated with vehicle or diazepam between 10 a.m. and 11 p.m. Intertrial intervals of 1, 3, 5, or 7 days were equally effective. The diazepam-induced increase in exploratory activity was significant over the first three uses of test animals. These data recommend reuse of mice to a maximum of three trials, throughout the daytime or evening hours of their lighting schedule.

Habituation of exploratory activity in mice: a screening test for memory enhancing drugs.

The habituation of exploratory activity was investigated as an experimental model of memory processes. Mice were given two sessions in a simple photo-cell activity cage and the decrease in activity at the second session (habituation) served as an index of retention. Retention decreased as the interval between sessions increased from 1 to 7 days. Retention was facilitated or impaired by post-session. IP injections of several drugs known respectively to improve [(+)-amphetamine, nicotine, physostigmine, strychnine] or impair (chlordiazepoxide, chlorpromazine, scopolamine) memory in other animal models. Memory facilitation or impairment only occurred if administration of the enhancing or impairing agent closely followed the first session, suggesting that the consolidation period was of limited duration. Post-session administration of presumably rewarding or noxious stimuli did not affect retention. Finally, retention was enhanced by several drugs which are used clinically for the treatment of memory disorders (bromocriptine, dihydroergotoxine, meclofenoxate, naftidrofuryl and piracetam). These results, consistent with classical learning data, suggest that habituation of exploratory activity in mice provides a simple but valid model of memory processes suitable for the screening of memory enhancing drugs.

Cholinergic influences on habituation of exploratory activity in mice.

Cholinergic influences on habituation of exploratory activity in mice.

Measurement of pharmacological depression of exploratory activity in mice: a contribution to the problem of time-economy and sensitivity.

Changes in exploratory behaviour in mice due to two variables, size of test enclosure and intensity of illumination, each at three levels were tested repeatedly over five exposures. The most suitable procedure for eliciting depressant effects of drugs on exploratory activity was to use a small enclosure (8×24 cm) with dim illumination (2 lx), and to partially habituate the animals to this environment before giving drugs. Under these conditions the amount of walking and rearing by untreated mice was about 70% of the maximal values obtained. It was also found that test sessions lasting for one minute provided sufficient information. In the selected “optimal” setting, the lowest effective depressant doses of chlorpromazine and barbitone were 0.3 mg/kg and 5.0 mg/kg, respectively, while under other conditions it was necessary to use higher doses of the drugs to obtain similar effects, and occasionally, increases in activity were also recorded. Since it took not more than 70 sec to test each mouse, up to 200 animals could be tested each day, which makes it possible to determine both dose- and time-response relationships quite rapidly. These results suggest ways in which experimental variables can be manipulated to “tune-up” exploratory behaviour and to make it more sensitive to specific types of psychotropic drugs.

Antagonistic effects of tryptamine and beta-phenylethylamine on the behaviour of rodents.

ACCORDING to Brodie and Shore, the behaviour of higher animals depends on neurohumoral agents produced in the diencephalon. Catecholamines such as noradrenaline and dopamine are said to act as ergotropic agents, whereas serotonin is their antagonistic trophotropic factor1,2. The essential validity of these concepts has been confirmed many times3,4. There are, however, some discrepancies concerning the supposed stimulating (ergotropic) effects of catecholamines; some results confirm their alerting action, but others point to a depressing effect5,6. We found7–11 that not only catecholamines, but also their amino-acid precursor L-dopa, suppress exploratory behaviour in mice, whereas amphetamine derivatives, as well as β-phenylethylamine and its amino-acid precursor phenylalanine, enhance it; there is a mutual antagonism between the two groups of substances. Serotonin too suppresses exploratory activity in mice and produces a Parkinson-like state in rats, similar to that produced by reserpine. β-Phenylethylamine antagonizes these effects of serotonin12. We concluded that β-phenylethylamine rather than catecholamines should be considered the ergotropic agent, while serotonin, as proposed by Brodie and Shore, is its antagonistic trophotropic factor. It seems to us that catecholamines may function differently in particular systems, but they do not seem to stimulate motor activity. Amphetamine and its derivatives may act by liberating β-phenylethylamine.

The inhibitory effect of amphetamine on exploration in mice.

Amphetamine has been shown to decrease exploratory activity in mice at moderate doses. The conditions under which it causes increased motility are defined as follows: dose levels above 10 mg/kg in combination with either

Studies on 6-azauridine and 6-azacytidine—II.: The effects of 6-azauridine on the central nervous system

The effects of 6-azauracil and its ribonucleoside—6-azauridine—on the central nervous system were compared in mice. It was shown that loss of the righting reflex, motor inco-ordination and analgesia are rather subtoxic effects, the values for the ed 50 being close to those of the ld 50 of both compounds. The antagonism towards various convulsant agents appears to be more specific, especially as antagonism to nicotine is concerned. The most sensitive indicator of central activity of both 6-azapyrimidines was found in the depression of exploratory activity in mice and rats. Conditioned avoidance behaviour was unaffected at very high doses. In all these tests the difference between 6-azauracil and 6-azauridine was only quantitative, the ribonucleoside being 2–4 times less active on a molar basis than the free base; however, the 50 to 100-fold increase in the activity of 6-azauridine after its direct injection into the cerebral ventricles of mice and cats, in which a typical behavioural pattern is evoked, suggests that penetration through the hemato-encephalic barrier is an important limiting factor with respect to the potentiality of 6-azauridine for exerting an action on the central nervous system. Qualitatively identical effects have been observed after intraventricular injection of 6-azauridine-5'-monophosphate and small amounts of this nucleotide have been detected in various regions of the cat brain after administration of 14C-labelled 6-azauridine into the cerebral ventricles. The possibility is discussed that central activity and carcinostatic effects of 6-azauracil and 6-azauridine are based on a common biochemical mechanism, namely inhibition of orotidylic acid decarboxylase resulting from the formation of 6-azauridine-5'-monophosphate.

THE ACTION OF INHIBITORS OF CATECHOL-O-METHYL-TRANSFERASE ON THE EXPLORATORY ACTIVITY OF MICE.

THE ACTION OF INHIBITORS OF CATECHOL-O-METHYL-TRANSFERASE ON THE EXPLORATORY ACTIVITY OF MICE.