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At least 1,207 records · Page 67Linked to original sources
PubMed2003

3,4-methylenedioxymethamphetamine (ecstasy) inhibits dyskinesia expression and normalizes motor activity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated primates.

Ecstasy [3,4-methylenedioxymethamphetamine (MDMA)] was shown to prolong the action of L-3,4-dihydroxyphenylalanine (L-DOPA) while suppressing dyskinesia in a single patient with Parkinson's disease (PD). The clinical basis of this effect of MDMA is unknown but may relate to its actions on either dopaminergic or serotoninergic systems in brain. In normal, drug-naive common marmosets, MDMA administration suppressed motor activity and exploratory behavior. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated, L-DOPA-primed common marmosets, MDMA transiently relieved motor disability but over a period of 60 min worsened motor symptoms. When given in conjunction with L-DOPA, however, MDMA markedly decreased dyskinesia by reducing chorea and to a lesser extent dystonia and decreased locomotor activity to the level observed in normal animals. MDMA similarly alleviated dyskinesia induced by the selective dopamine D2/3 agonist pramipexole. The actions of MDMA appeared to be mediated through 5-HT mechanisms because its effects were fully blocked by the selective serotonin reuptake inhibitor fluvoxamine. Furthermore, the effect of MDMA on L-DOPA-induced motor activity and dyskinesia was partially inhibited by 5-HT1a/b antagonists. The ability of MDMA to inhibit dyskinesia results from its broad spectrum of action on 5-HT systems. Serotoninergic receptors appear to play an important modulatory role in l-DOPA-induced dyskinesia, and this study may provide a framework for the use of serotoninergic agents in the treatment of L-DOPA-induced dyskinesia.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMedDate not supplied

Evaluation of psychopharmacological effects of petroleum ether extract of Cuscuta reflexa Roxb. stem in mice.

The petroleum ether extract of Cuscuta reflexa Roxb. stem (PECR) was evaluated for its psychopharmacological activities in several experimental models using Swiss albino mice. The PECR was found to cause significant reduction in spontaneous activity and exploratory behavioral profiles. It also showed reduction in muscle relaxant activity by rotarod, 30 degrees inclined screen tests and showed significant analgesic properties as well as potentiated remarkably the pentobarbitone sodium, diazepam and meprobamate--induced sleeping time. All these results were compared with respective controls for the evaluation of significance. The presence of steroids in the PECR might he responsible for psychopharmacological activities.

Alkanes↗
PubMedDate not supplied

Multiple administration of carbamazepine, typical and atypical antidepressant drugs on clonidine-induced hypoactivity in mice.

The chronic effects of carbamazepine were compared with those of typical and atypical antidepressant drugs on clonidine--induced hypoactivity in mice. The results indicated that clonidine at a dose of 0.05-0.10-0.15 mg/kg i.p. produced a dose-dependent depressant effect on the exploratory behavior, as shown by the marked reduction in ambulation and rearing in an "open-field" test. Chronic pretreatment with imipramine 20 mg/kg i.p. and desipramine 5-10 mg/kg i.p. for 14 days resulted in a significant reduction in clonidine-induced hypoactivity. Repeated pretreatment with atypical antidepressant drugs (trazodone 5-10 mg/kg i.p.:, fluoxetine 5-10 mg/kg i.p., or rubidium chloride 24-48 mg/kg i.p.) as well as carbamazepine 10-20 mg/kg i.p., had no significant effect on clonidine-induced hypoactivity. In summary, these findings provide further evidence for a subsensitivity of presynaptic alpha 2-adrenoceptors in animals chronically treated with imipramine or desipramine and a behavioural profile of carbamazepine similar to that of atypical antidepressant drugs.

Animals↗
PubMed1991

Neurobehavioral development of rats exposed to toluene through maternal milk.

Organic solvents have been detected in the milk of workers in the rubber industry exposed during gestation to a mixture of solvents at average concentrations lower than the currently accepted occupational limit of exposure (100 ppm). The objective of the present study was to determine if exposure of rat offspring to toluene during lactation, through maternal milk, would affect the developing brain. Three month old, lactating Wistar rats were injected with toluene (1.2 g/kg, sc, N = 10) daily from lactation day 2 (day of delivery = day 1) to day 21. Controls (N = 9) were injected with the vehicle (corn oil). Offspring (7 pups per liter) were evaluated for neurosomatic development and exploratory behavior before weaning and behavior in the open field. A second group of toluene-treated rats (N = 6) and controls (N = 6) was used to evaluate behavior of the offspring in the open-field on day 35 and performance in a shuttle box in adulthood. Toluene levels in blood and milk after a single 1.2 g/kg sc injection were studied in a third group of rats on lactation day 10. Toluene levels in milk 4 h after a single injection (10.3 +/- 6.2) were 5 times higher than in blood (2.1 +/- 0.8). No effects of treatment on offspring development or on any of the behavioral tests were observed. Sex differences were observed in open-field behavior and performance in the shuttle box. The present results suggest that exposure of pups to high concentrations of toluene through maternal milk does not result in blood levels high enough to affect growth or development.

Animals↗
PubMed1990

Effect of chronic cadmium exposure on locomotor behaviour of rats.

Growing male rats were exposed to cadmium (Cd, 100 micrograms/kg, ip) for 51 days and the effect on the different components of locomotor behaviour was assessed on days 38, 46 and 51 of Cd exposure. Significant decrease in distance travelled, stereotypic time and movements, ambulatory time and vertical movements were observed in Cd-exposed rats, whereas the time of rest was increased. The number of entries into the inner as well as the outer squares and the total time spent in the inner squares of the floor area were significantly reduced. Results indicate that Cd exposure results in a general depression in all aspects of motor behaviour leading to decrease in gross locomotor activity. The involvement of an exaggerated emotional reactivity in the behavioural expression of the Cd-treated animals is also emphasized.

Acetates↗
PubMed1990

Comparison of brain structure volumes in Insectivora and primates. IX. Trigeminal complex.

Volumes of the trigeminal complex (TR) were measured in 30 species of Insectivora, 3 species of Scandentia, 18 species of prosimians, 26 species of non-human simians and in man. The relative size showed a definite tendency to decrease from 159 in Insectivora to 56 in simians (expressed as size indices). The difference in the development of the TR between Insectivora and Primates is explained by differences in the role of their oro-facial region in exploratory behavior. The largest size was found in semiaquatic Insectivora (average 283). In semiaquatic forms, the reduction of the olfactory centers is compensated by an increase in TR size. The extremely long vibrissae innervated by the trigeminal nerve seem to have a teletactile function in detecting vibrations in the water produced by potential prey.

Animals↗
PubMed1989

Evidence for cholinergic participation in frontal cortical potentials evoked by single impulse stimulation in the locus coeruleus area of freely moving rats.

Single impulse stimulation in the area of locus coeruleus (LC) in freely moving rats evokes bilateral symmetrical potentials (EP) in the frontal cortex. Threshold intensity for this potential was higher when the stimulus electrode was in the LC than in the cholinergic dorsal parabrachial nucleus lateral of LC. Amplitudes and peak times of this EP were constant during relaxed wakefulness, exploratory behavior and unaffected by beta-blockade (propranolol, 2.5 mg/kg i.p.). Their amplitudes were strongly decreased and the peak times of later negativity (N50) were prolonged during slow wave sleep and by muscarinic blockade with scopolamine (0.5 mg/kg i.p.) which induced active behavior and synchronized EEG. These data suggest a direct participation of cholinergic structures in cortical potential evoked by electrical LC stimulation. Relations between stimulus effect and behavior regulating systems are discussed.

Animals↗
PubMedDate not supplied

[Characteristics of the psychotropic action of melatonin in relation to the dosage and time of day].

When administered in a low dose (0.1 mg/kg) the main pineal hormone melatonin decreased the locomotor activity and exploratory behavior of rats in the open field both during the light and dark phases of the day. High doses (1.0 and 10.0 mg/kg) were effective only at night hours (01.00-03.00). After administration of 0.1 mg/kg of melatonin no changes in the main parameters and rhythmicity of forced swimming occurred irrespective of the time of use. However the effect of 1.0 mg/kg of the hormone in the daytime manifested itself in an increase of the immobility and a decrease of the depression index.

Animals↗
PubMed1988

Lesions in the mesencephalic reticular formation change open field and thirst motivated labyrinth behaviour of rats.

Open field behaviour and thirst motivated running through two labyrinth variants were compared before and after bilateral symmetric lesions of the anterior part of the dorsolateral parabrachial nucleus (PBl) and in the anterior mesencephalic area cuneiformis (CU), both n = 9, on 4-month-old male Long-Evans rats. CU-rats were characterized by abolished visual placing responses, aphagia or hypophagia which was limited up to the 15th postoperative day, ambulatory hyperactivity, reduced climbing and grooming, but enhanced rearing. Their preoperatively learnt thirst motivated labyrinth passage remained unimpaired but their drinking behaviour was persistently changed. They interrupted drinking several times and regularly did not empty the cups. Thirst motivation was evidently reduced after CU-lesions. PBl-rats were ambulatory hypoactive and slowed with accelerated habituation, reduced climbing and changed incline-plane behaviour. A slight hypophagia was generally overcome after the 5th postoperative day. Labyrinth performance of PBl-rats was evidently changed with significantly slower runs and impaired differentiation of the second labyrinth type in which passage duration, errors and even duration of licking were enhanced. Water intake was less reduced than in CU-rats. Both nuclei include parts of the "mesencephalic locomotor region", but contribute differently to the regulation of spontaneous and goal-directed behaviour.

Animals↗
PubMed1977

Following their companions as a form of exploration for human infants.

Infants' following of other persons, often considered a measure of attachment, qualified as a form of exploration. The results of the first experiment indicated that following can be a means of investigating novel leaders: 16 9--12-month-old infants were as likely to follow an unfamiliar woman as they were the parent and were reliably more likely to follow a moving toy. The second and third experiments assessed the extent to which the experience of following familiar persons promotes learning about the environment. Infants who followed their mothers to 1 place were more likely later to investigate a similar place than those who initially either locomoted independently (experiment 2) or were transported by their mothers (experiment 3). The findings suggested that infants' transactions with the environment need not be considered antithetical to their social behavior.

Child Behavior↗
PubMed1983

The effects of lead on the developing central nervous system of the rat.

Biochemical and structural development of the cerebral cortex of rat pups is delayed by low levels of lead administered in the dam's drinking water during gestation and suckling periods. These changes in brain development coincide with delays in the development of exploratory and locomotor activity and impaired learning. Subsequent cross-fostering experiments have shown that delays in synaptogenesis and in the development of exploratory behavior were attributed entirely to the prenatal, as opposed to the postnatal, exposure to lead at the low dose levels utilized. Examination of the variations in blood lead concentrations in pups and dams during gestation and until weaning at 21 days of postnatal age indicated that a substantial increase in blood lead concentrations occurred late in pregnancy. At 200 mg of Pb/liter of drinking water, peak blood Pb concentrations were observed to be approximately 60 micrograms/dl in dams and 80 micrograms/dl in pups on the 20th day of gestation. By the 10th postnatal day blood Pb concentrations had decreased to 35 micrograms/dl in dams and 40 microgram/dl in pups despite an increased consumption of drinking water containing the same concentration of Pb during this period. (Delays in cerebral cortical development were observed after 10 days of postnatal age). Tracer studies utilizing 203Pb indicate that the rate of Pb absorption was substantially increased in the pregnant, relative to the non-pregnant, dam. Although a similar increase in 45Ca absorption was also observed during pregnancy, increases in Pb absorption were enhanced by Pb-pretreatment, whereas Ca absorption was independent of Pb-pretreatment. From this data it is concluded that the apparently greater sensitivity of postnatal development on prenatal Pb exposure is secondary to enhanced Pb absorption in the pregnant rat. In vitro metabolic studies in isolated cerebral cortex slices taken from 15 day old rat pups exposed to Pb revealed increased glucose and oxygen consumption in response to elevations in the potassium concentration of the incubation media. This evidence of metabolic uncoupling in the immature rat cerebral cortex may be causally related to the measured delays in brain development.

Animals↗
PubMed1984

Adverse behavioral effects of the anticholinesterase poisoning protector pralidoxime methanesulfonate.

Pralidoxime methanesulfonate (P2S) has anticholinesterase protective properties, but it also has an array of gastrointestinal (GI) symptoms. Because such a symptom would be disadvantageous to occupational workers who handled and used organophosphorus anticholinesterase continuously, and to soldiers who have had oral pretreatment in a situation where anticholinesterase agent poisoning is a possibility, this question was investigated in rats using three behavioral paradigms to evaluate the feasibility of the oral prophylactic regimen. These are: (1) conditioned taste aversion (CTA), (2) operant behavior and (3) spontaneous locomotor activity (SMA); these three behavioral parameters are analogous to toxicant-induced gastrointestinal (GI) disturbances, performance of learned tasks and behavioral arousal, respectively. Dose-response studies of P2S in dose levels of 0.2, 0.4, 0.8 and 1.6 gm/kg (P.O.) were evaluated. The results consistently demonstrated that only the highest dose significantly produced marked decreases in consumption of flavored solution associated with its ingestion, suppressed keypress response maintained under a 20-response fixed-ratio schedule of water presentation, and inhibited SMA. By inference, if CTA, operant behavior and SMA are appropriate paradigms, P2S, on an acute single oral high dose level, would cause GI disturbances, impair task performance and induce sedation in man.

Animals↗
PubMed1993

Guidance of retinal fibers in the optic chiasm.

At the optic chiasm of vertebrates, there occurs a sharp divergence in the destination of retinal ganglion cell axons as they are on their way to more central targets. Recent studies in the mouse indicate that the growth cones of each set of fibers diverge close to the midline of the optic chiasm, at the borders of a palisade of immature radial glia. Static and dynamic views of retinal growth cones in this decision region reveal that extensive exploratory behavior and selective retraction of parts of the growing tips of uncrossed fibers, in response to cellular cues at the midline, is a major event in the guidance of these fibers. In vitro experiments further show that presumptive crossed and uncrossed fibers differ in their responses to contact with cells from the optic chiasm. As with other instances of selective guidance of fibers at midline structures, the divergence of crossed and uncrossed retinal fibers therefore involves a selective remodeling of their growing tips and transitory axon-cell contacts during growth at the optic chiasm, presumably due to biochemical heterogeneity among crossed and uncrossed ganglion cell fibers.

Animals↗
PubMed1993

Pairing the cholinergic agonist carbachol with patterned Schaffer collateral stimulation initiates protein synthesis in hippocampal CA1 pyramidal cell dendrites via a muscarinic, NMDA-dependent mechanism.

Effects of afferent stimulation on local synthesis of protein in CA1 pyramidal cell dendrites were studied using light microscope autoradiography. Tissue was fixed with paraformaldehyde immediately after 3 min exposure to 3H-leucine in order to trap 3H associated with macromolecules. The rate of 3H-leucine incorporation into dendrites of resting hippocampal slices was 10% the rate of incorporation into cell somata. Ninety percent of the incorporation into the somata was inhibited by cycloheximide (300 microM); none of the incorporation into dendrites was blocked by cycloheximide. Thus, there is no measurable extramitochondrial synthesis of protein in the dendrites of the resting slice. Slices were exposed to 50 microM carbachol and the Schaffer collateral afferents to the CA1 pyramidal cells were stimulated intermittently at 10 Hz over a 20 min period. In this case, 3H incorporation into dendrites was increased almost threefold over resting levels, with no effect on label over the cell somata. There was no associated increase in uptake of free 3H-leucine, and the increase in label was completely blocked by cycloheximide. Thus, associating carbachol and afferent stimulation appears to activate de novo protein synthesis in the dendrites. Neither the carbachol alone nor the Schaffer collateral stimulation alone increased synthesis. The activation of dendrite synthesis was completely blocked by 5 microM atropine, and also by 50 microM D-aminophosphonovalerate. It did not occur when carbachol was paired with steady stimulation of the Schaffer collaterals at 1 Hz for 20 min, rather than with the patterned high-frequency stimulation. Thus, associating a cholinergic agonist with a level of neural activity that occurs in CA3 and CA1 pyramidal cells during exploratory behavior (Muller et al., 1987) initiates local protein synthesis in target dendrites. This effect is dependent on muscarinic cholinergic receptors and NMDA-type glutamate receptors. The possible relationship of this phenomenon to mechanisms of learning is discussed.

2-Amino-5-phosphonovalerate↗
PubMed1995

Personal and situational factors in drug use as perceived by kibbutz youth.

Sixteen 17-year-old kibbutz members, seven of them smokers, and nine nonsmokers of hashish, assessed the probability that a young person of similar background would use drugs. Two sources of information were manipulated bifactorially: personal predisposition (curiosity, risk-taking, and existential meaning) and the level of group pressure to smoke hashish. It was found that hashish smokers assigned meaningful importance to a combined influence of the two factors, while the nonsmokers considered only group pressure to be important. A tool based on the measurement method examined in this study is proposed for predicting the probability of drug use among adolescents.

Adolescent↗